Asymmetric　reduction　of　3-chloropropiophenone　with　Saccharomyces　cerevisiae　in　aqueous　system　was　studied.　The　results　showed　that　the　preference　product　configuration　was　(S)-3-chloro-1-phenylpropanol,　and　the　reduction　was　catalyzed　by　a　single　reductase　or　several　isozymes　with　the　same　catalytic　characteristics.　In　the　concentration　range　investigated,　neither　substrate　nor　product　inhibitions　were　found,　but　the　toxicity　of　product　which　induced　the　cell　inactivation　prevented　the　yield　from　elevation.　The　proper　concentration　of　inclusion　complexes　in　the　reaction　system　assisted　to　improve　the　yield,　for　example,　when　the　concentration　of　Tween-80　and　β-cyclodextrin　was　2.0　and　5.0　mmol/L,　the　yields　would　be　increased　from　the　control　of　64.7%　to　73.8%　and　70.6%,　respectively.　The　additives　with　the　abilities　of　inclusion　and　improvement　of　cell　membrane　permeability　would　take　better　effect　on　the　yield　than　those　only　with　the　ability　of　inclusion.