To investigate the effect of Eupolyphaga sinensis Walker ethanol extract (ESWE) on human prostate cancer PC3 cells growth,migration and invasion in vitro,and to study its mechanism.MTT assay was used to determine the toxicity of ESWE on human prostate cancer PC3 cells.Cell apoptosis were analyzed by flow cytometry and Hoechst 33258 staining.Transwell assay and cell scratch test were used to detect the effect of ESWE on migration and invasion of PC3 cells.Western blot assay were employed to detect the expressions of metastasis related proteins MMP-2 and MMP-9 after different concentrations of ESWE were used to treat human breast cancer．The results showed that ESWE can inhibit the growth,migration and invasion of human prostate cancer PC3 cells in a concentration-dependent manner.Furthermore,ESWE could reduce the protein expression of MMP-2 and MMP-9.The results of flow cytometry and Hoechst 33258 staining showed that ESWE could not induce PC3 cell apoptosis In conclusion,ESWE can inhibit the proliferation，migration，invasion of human prostate cancer cell line PC3,and the mechanism may be associated with the inhibition of the expression of MMP-2 and MMP-9.