Abstract: BCap-37 cells were given 10μmol/L,30μmol/L,90μmol/L of daidzein and genistein 1～4 days.Growth curve test and the incorpoation of ³H-TdR served as the index to reflect prolifertive activity of BCap-37 cells.Cell cycle of BCap-37 cells were measured by Flow Cytometery.It was showed that BCap-37 cells were inhibitied after they were given 1～9×10⁵ mol/L of genistein 3～4 days.Antiproliferative activity of genistein was positively related to cultivtive time and dose.Whereas daidzein was not effect proliferation of BCap-37 cells at the same dose.Antiproliferative activity of genistin was significant at 3×10⁵ mol/L.Proliferation index of BCap-37 cells was obviously decreased after they were exposured to genistein for 4 days.BCap-37 cells were blocked in G₁ phase.The results suggest that Genistein can inhibit proliferation of BCap-37 cells.