Objective To study the application value of magnetic resonance imaging（MRI）,transrectal ultrasound（TRUS）combined with serum prostate-specific antigen（PSA）in the diagnosis of prostate cancer．Methods A total of 140 patients with suspected prostate cancer who were examined at Wuxue First People's Hospital from January 2020 to January 2023 were enrolled．MRI and TRUS examinations were performed,and serum PSA levels were tested．The surgical pathology results of the patients were used as the gold standard．The missed diagnosis and misdiagnosis in single MRI,TRUS,serum PSA and combined diagnosis were observed,consistency was analyzed,and the diagnostic sensitivity,specificity,and accuracy of each single diagnosis and combined diagnosis were calculated．Results There were 81 cases of prostate cancer and 59 cases of non-prostate cancer confirmed by surgical pathology results．The serum PSA level of prostate cancer patients was higher than that of non-prostate cancer patients（P<0.05）．The difference between the diagnosis of prostate cancer by single MRI,TRUS or PSA and the results of surgical pathology was with general consistency（Kappa=0.641,0.624,0.536,all P<0.001）,and the consistency of combined diagnosis and surgical pathology results was good（Kappa=0.906,P<0.001）．The sensitivity,specificity,and accuracy of combined diagnosis were higher than single MRI,TRUS,serum PSA and the combination of two diagnostic methods（P<α,α=0.007）．Conclusions In the diagnosis of prostate cancer,single MRI,TRUS and serum PSA diagnosis all have risks of missed diagnosis and misdiagnosis．Combined diagnosis can make up for the shortcomings of single diagnosis and improve the diagnostic accuracy of prostate cancer．