Objective:To evaluate the diagnostic performance of the Prostate Imaging Reporting and Data System version 2.1(PI-RADS v2.1)for clinically significant prostate cancer(CSPCa)in the peripheral zone(PZ),transitional zone(TZ)and multiple zones(MZs).Methods:We retrospectively studied the clinical data on 108 patients undergoing multiparametric magnetic resonance imaging(mpMRI)and transperineal prostate biopsy in our hospital from January 2021 to January 2023.Using PI-RADS v2.1,we ex-amined the MR images of the patients with suspected PCa,compared the PI-RADS v2.1 scores with the results of prostate biopsy,and analyzed the correlation of the PI-RADS v2.1 scores with CSPCa.We calculated the area under the receiver operating characteristic(ROC)curve(AUC),and described the diagnostic performance of PI-RADS v2.1 for CSPCa in the PZ,TZ and MZs.Results:Transperineal prostate puncture biopsy was successfully completed in all the patients,which revealed 66(61.11％)cases of CSPCa with Gleason score(GS)7-10.Suspected CSPCa was observed in 45(95.74％)of the 47 PZ lesions,8(47.06％)of the 17 TZ le-sions,and 40(90.91％)of the 44 MZ lesions.The PZ,TZ and MZ lesions diagnosed by PI-RADS v2.1 were significantly correlated with CSPCa(r=0.492,P＜0.001).The AUCs of PI-RADS v2.1 for PZ,TZ and MZs were 0.644,0.732 and 0.811,with specificities of 66.8％,57.6％and 62.1％,and sensitivities of 57.2％,78.4％and 93.2％,respectively.The negative predictive values were 46.5％,85.7％and 79.2％,and the positive predictive values 76.2％,43.4％and 84.8％,respectively.Conclusion:The PI-RADS v2.1 score has a high diagnostic value for CSPCa in the PZ,TZ and MZs,with the best performance for that in the MZs.