Abstract: Objective: To study the inhibition of akr1c3 expression by phytoestrogen genistein(Gen), thereby inhibiting the growth of castration-resistant prostate cancer(CRPC), and provide a theoretical basis for the clinical treatment of CRPC with genistein. Methods: 22RV1, VCaP, RWPE-1 cells were cultured in a hormone-free serum environment, and treated with different concentrations (0, 12.5, 25, 50, 100) μmol/L of GEN for 48 h. CCK-8 was used to detect cell proliferation activity. AKR1C3 siRNA and AKR1C3 inhibitor(ASP-9521) were combined with GEN to interfere with 22RV1 and VCaP cells, respectively, and the expression levels of PSA and AKR1C3 proteins in the cells were detected by Western blot. Results: Genistein could inhibit castration and resist the growth of prostate cancer. Western blot results showed that GEN could inhibit the expression of PSA and AKR1C3 proteins, and when combined with AKR1C3 siRNA and AKR1C3 inhibitor (ASP-9521), the inhibitory effect on AKR1C3 was more significant. Conclusion: Genistein expression in prostate cancer cells can resist by inhibiting AKR1C3 castration, thereby inhibiting cell proliferation CRPC.