Abstract: Objective:To explore the measure to avoid the missed diagnosis of prostate carcinoma in patients with normal level of prostate specific antigen(PSA).Methods:Two hundred and three prostate hyperplasia patients with normal PSA level were treated with transurethral resection of the prostate,and the clinical data of 6 cases with prostate carcinoma diagnosed by pathological examination were retrospectively analyzed.Results:The signs of prostate carcinoma in 6 cases with prostate carcinoma were not found by the conventional ultrasonography examination and anus digital,and the 6 patients were the first visit to hospitalization.Among 6 cases,1 case was undifferentiation,1 case was middle differentiation with severe condition of prostate carcinoma,the disease developed rapidly,and 2 cases died in a short period of time.The rest 4 patients were highly differentiation prostate carcinoma,and still live now.Conclusions:The normal level of prostate specific antigen can be found in the early incidental prostate carcinoma and progressive prostate carcinoma,which can lead to the missed diagnosis.The application of ultrasound combined with nuclear magnetic resonance,especially transrectal ultrasonography of prostate and prostate specific antigen rate,should be considered.The prostatic puncture in suspected patient should be performed to improve the early diagnosis rate of prostate carcinoma.