Objective To detect the expression level of cell division cycle gene 20 (CDC20) in prostate cancer (PC) tissues and analyze the effect on the clinicopathological characteristics and prognosis of PC patients. Methods To collect the prostatic tissues of 134 PC patients and benign prostate hyperplasia tissues of 134 patients with benign prostate hyperplasia who underwent surgical treatment in the 988th Hospital of Joint Logistics Support Force from January 2016 to December 2018. qRT-PCR, Western blotting and immunohistochemical method were used to detect the expression of CDC20 in PC tissues and benign prostate hyperplasia tissues. According to the immunohistochemical score, the PC patients were divided into CDC20 high expression group(n=69) and CDC20 low expression group (n=65). The clinicopathological characteristics, 3-year overall survival rate and disease progression-free survival rate were compared between the two groups. Cox regression analysis were performed to analyze the risk factors affecting the survival of patients after surgery. Results The results of qRT-PCR and Western blotting showed that the relative expression levels of CDC20 mRNA and protein were higher in PC tissues than in benign prostate hyperplasia tissues with statistically significant difference (mRNA: 1.96±0.34 vs. 0.37±0.12, P=0.003; protein: 1.02±0.08 vs. 0.15±0.06, P<0.001). The immunohistochemical test results showed that the positive expression rate and high expression rate of CDC20 were higher in PC tissues than in benign prostate hyperplasia tissues [CDC20 positive expression rate: 80.6% (108/134) vs. 8.9% (12/134), P<0.001;CDC20 high expression rate: 51.5% (69/134) vs. 0.0% (0/134), P<0.001]. The 3-year overall survival rate and disease progression-free survival rate were lower in CDC20 high expression group than in CDC20 low expression group with statistically significant difference [3-year overall survival rate: 69.6% (48/69) vs. 87.7% (57/65), P=0.012; 3-year disease progression-free survival rate: 62.3% (43/69) vs. 80.0% (52/65), P=0.020]. Gleason score >7 points, cT stage >cT_2c stage, T stage >T₂ stage, and CDC20 immunohistochemical score ≥8 points were independent risk factors affecting postoperative survival of PC patients (P<0.05). Conclusions The increased expression of CDC20 in PC tissue might mean the progress of PC. CDC20 immunohistochemical score ≥8 points suggests a poor prognosis for patients, so is expected to become a tumor marker for judging the prognosis of PC.