<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-12-15</periodOfReport>

    <issuer>
        <issuerCik>0001390332</issuerCik>
        <issuerName>STONE TAN CHINA ACQUISITION CORP.</issuerName>
        <issuerTradingSymbol>STTA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001319244</rptOwnerCik>
            <rptOwnerName>INTEGRATED CORE STRATEGIES (US) LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MILLENNIUM MANAGEMENT LLC</rptOwnerStreet1>
            <rptOwnerStreet2>666 FIFTH AVENUE, 8TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10103-0899</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>May be deemed a group member.</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001446811</rptOwnerCik>
            <rptOwnerName>COGNIZANT HOLDINGS, LTD.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>MILLENNIUM INTERNATIONAL MANAGEMENT LP</rptOwnerStreet1>
            <rptOwnerStreet2>666 FIFTH AVENUE, 8TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10103-0899</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>May be deemed a group member.</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001426821</rptOwnerCik>
            <rptOwnerName>MILLENNIUM INTERNATIONAL MANAGEMENT LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>666 FIFTH AVENUE, 8TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK, NY 10103</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10103-0899</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>May be deemed a group member.</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001446830</rptOwnerCik>
            <rptOwnerName>MILLENNIUM INTERNATIONAL MANAGEMENT GP LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>666 FIFTH AVENUE, 8TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10103-0899</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>May be deemed a group member.</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001273087</rptOwnerCik>
            <rptOwnerName>MILLENNIUM MANAGEMENT LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>666 FIFTH AVENUE, 8TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10103-0899</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>May be deemed a group member.</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001017456</rptOwnerCik>
            <rptOwnerName>ENGLANDER ISRAEL A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MILLENNIUM MANAGEMENT LLC</rptOwnerStreet1>
            <rptOwnerStreet2>666 FIFTH AVENUE, 8TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10103-0899</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>May be deemed a group member.</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3987950</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F8"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-12-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>50000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.225</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>190510</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-12-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>20000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.22</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>210510</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                    <footnoteId id="F8"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">As of the date of this filing, Integrated Core Strategies (US) LLC, a Delaware limited liability company (&quot;Integrated Core Strategies&quot;), is the beneficial owner of 3,987,950 shares of the common stock, par value $0.0001 per share (&quot;Common Stock&quot;), of Stone Tan China Acquisition Corp., a Delaware limited liability company (the &quot;Issuer&quot;), and Cognizant Holdings, Ltd., an exempted limited company organized under the laws of the Cayman Islands (&quot;Cognizant Holdings&quot;), is the beneficial owner of 210,510 shares of the Issuer's Common Stock.</footnote>
        <footnote id="F2">As of the date of this filing, Integrated Core Strategies also held 1,882,300 warrants to purchase the Company's Common Stock (&quot;Warrants&quot;). Each Warrant entitles the holder to purchase one share of the Company's Common Stock at a price of $5.50. Each Warrant will become exercisable upon the Company's completion of a business combination, provided that the Company has an effective registration covering the shares of Common Stock issuable upon the exercise of the Warrants. The Warrants will expire on October 15, 2011, or earlier upon redemption. As of the date of this filing, the Company has not announced the completion of a business combination and therefore, the Warrants are not currently exercisable.</footnote>
        <footnote id="F3">Millennium Management LLC, a Delaware limited liability company (&quot;Millennium Management&quot;), is the general partner of the managing member of Integrated Core Strategies, and consequently may be deemed to have shared voting control and investment discretion over securities owned by Integrated Core Strategies.</footnote>
        <footnote id="F4">Millennium Management is also the general partner of the 100% shareholder of Cognizant Holdings, and consequently may be deemed to have shared voting control and investment discretion over securities owned by Cognizant Holdings.</footnote>
        <footnote id="F5">Millennium International Management LP, a Delaware limited partnership (&quot;Millennium International Management&quot;), is the investment manager to Cognizant Holdings, and consequently may be deemed to have shared voting control and investment discretion over securities owned by Cognizant Holdings.</footnote>
        <footnote id="F6">Millennium International Management GP LLC, a Delaware limited liability company (&quot;Millennium International Management GP&quot;), is the general partner of Millennium International Management, and consequently may be deemed to have shared voting control and investment discretion over securities owned by Cognizant Holdings.</footnote>
        <footnote id="F7">Israel A. Englander (&quot;Mr. Englander&quot;) is the managing member of Millennium Management and of Millennium International Management GP, and consequently may be deemed to be the beneficial owner of any securities beneficially owned by Integrated Core Strategies and/or Cognizant Holdings, as the case may be.</footnote>
        <footnote id="F8">The foregoing should not be construed in and of itself as an admission by Millennium International Management, Millennium International Management GP, Millennium Management or Mr. Englander as to beneficial ownership of the securities owned by Integrated Core Strategies and/or Cognizant Holdings, as the case may be.</footnote>
    </footnotes>

    <remarks>*INTEGRATED CORE STRATEGIES (US) LLC, By: Integrated Holding Group LP, its managing member, By: Millennium Management LLC, its general partner, By: David Nolan, Co-President</remarks>

    <ownerSignature>
        <signatureName>*David Nolan, Co-President</signatureName>
        <signatureDate>2008-12-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
