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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-04-06</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000789868</issuerCik>
        <issuerName>AMERICAN DAIRY INC</issuerName>
        <issuerTradingSymbol>ADY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001279329</rptOwnerCik>
            <rptOwnerName>SHEN NEIL NANPENG</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>SUITE 2215, TWO PACIFIC PLACE</rptOwnerStreet1>
            <rptOwnerStreet2>88 QUEENSWAY</rptOwnerStreet2>
            <rptOwnerCity>HONG KONG</rptOwnerCity>
            <rptOwnerState>F4</rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription>CHINA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-04-06</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-08-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2333</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6333</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1883366</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Sequoia</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Restricted stock grant for services rendered as a director for the period January 1, 2009 through December 31, 2009.</footnote>
        <footnote id="F2">Restricted stock grant for services rendered as a director for the period January 1, 2010 through July 31, 2010.</footnote>
        <footnote id="F3">Represents 98,450 shares held by Sequoia Capital China I LP, 11,312 shares held by Sequoia Capital China Partners Fund I LP and 15,238 shares held by Sequoia Capital China Principals Fund I LP (together &quot;Sequoia Fund I&quot;) and 1,533,647 shares held by Sequoia Capital China Growth Fund I LP, 36,574  shares held by Sequoia Capital China Growth Partners Fund I LP and 188,145 shares held by Sequoia Capital China GF Principals Fund I LP (together &quot;Sequoia Growth&quot;). The reporting person is a Managing Director of SC China Holding Limited, the General Partner of each of Sequoia Capital China Management I, L.P., the General Partner of Sequoia Fund I and Sequoia Capital China Growth Fund Management I, L.P., the General Partner of Sequoia Growth.  The reporting person disclaims beneficial ownership of these shares except to the extent of his pecuniary interest therein.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Neil Nanpeng Shen</signatureName>
        <signatureDate>2010-08-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
