Firstly,　the　pure　water　flux,　average　pressure　of　bubble　point　minus　maximum　pressure　of　bubble　point,　the　pure　water　flux　plus　average　pressure　of　bubble　point　minus　maximal　pressure　of　bubble　point　were　selected　as　the　performance　indices　of　poly(vinylidene　fluoride)　(PVDF)/cellulose　acetate　(CA)　blend　microfiltration　membrane.　An　orthogonal　table　with　nine　factors　and　four　levels　L32(49)　for　the　PVDF/CA　system　was　designed　to　study　the　performance　of　PVDF/CA　blend　microfiltration　membrane.　Secondly,　the　linear　multi-regression　model　with　standardized　coefficients　matrix　was　used　to　study　the　effects　of　nine　factors.　The　results　showed　that:　when　pure　water　flux　was　taken　as　the　objective　function,　blend　ratio　of　PVDF/CA,　solid　content,　additive　content　and　gelation　temperature　were　the　major　influence　factors;　when　average　pressure　of　bubble　point　minus　maximum　pressure　of　bubble　point　was　taken　as　the　objective　function,　solid　content　was　the　major　influence　factor;　when　the　pure　water　flux　plus　average　pressure　of　bubble　point　minus　maximal　pressure　of　bubble　point　was　taken　as　the　objective　function,　solid　content　was　the　major　influence　factor.　After　analyzing　the　SEM　photographs　and　experimental　results,　the　optimum　condition　for　preparing　the　PVDF/CA　blend　microfiltration　membrane　was　as　follows:　blend　ratio　of　PVDF/CA　4:1,　solid　content　12%,　additive　content　2%-3%,　gelation　temperature　30-35°C.