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

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2006-12-01</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000889348</issuerCik>
        <issuerName>CPI AEROSTRUCTURES INC</issuerName>
        <issuerTradingSymbol>CVU</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001349989</rptOwnerCik>
            <rptOwnerName>Bazaar Harvey J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CPI AEROSTRUCTURES, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>60 HEARTLAND BLVD.</rptOwnerStreet2>
            <rptOwnerCity>EDGEWOOD</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>11717</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Options to purchase common shares</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>6.75</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2006-12-01</value>
            </exerciseDate>
            <expirationDate>
                <value>2011-11-30</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common shares</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3333</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Harvey Bazaar</signatureName>
        <signatureDate>2006-12-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
