〔Abstract〕 To investigate the role of prostate-specifific antigen isoform 2(p2 PSA) and its related marker prostate health index(PHI) in the diagnosis of prostate cancer, and to further study the effect of different levels of preoperative PHI on the biochemical recurrence(BCR) of prostate cancer. Serum p2 PSA,total prostate specifific antigen(tPSA) and free prostate specifific antigen(fPSA)were determined in 38 patients with prostate cancer and 69 patients with benign prostatic hyperplasia(BPH) confirmed by pathology.The BCR of PCA patients after 12 months was followed up. The optimal cutoff value of PHI was determined by using the ROC curve. The patients were divided into low PHI(PHI≤71.28) and high PHI(PHI>71.28) groups. The recurrence rate of BCR and the effect of different levels of PHI on BCR after surgery was compared. Age,tPSA,fPSA,p2 PSA and PHI between prostate cancer group and BPH group had significant statistical differences(P<0.05). ROC curve analysis showed that the areas under curves(AUC) of tPSA, p2 PSA, f-PSA and PHI in the diagnosis of prostate cancer were 0.637(95%CI: 0.529～0.745), 0.731(95%CI: 0.630～0.833) and 0.845(95%CI: 0.770～0.920) respectively. The diagnostic efficacy of PHI and p2 PSA in prostate cancer was better than that of fPSA,which had higher diagnostic value(AUC>0.7). The results showed that the biochemical recurrence of high PHI group was significantly higher than that of low PHI group after 12 months of follow-up, and the difference was statistically significant(P=0.015). The diagnostic efficacy of PHI for prostate cancer is better than those of tPSA and fPSA,which can be used as an auxiliary diagnostic method for prostate cancer. The PHI=71.28 might be the critical value for evaluating the biochemical recurrence rate of prostate cancer and it provides some valuable references for predicting the biochemical recurrence rate of prostate cancer before operation.