Abstract：【Objective】To explore the diagnostic value of magnetic resonance imaging（MRI）combined transrectal ultrasound （TRUS）to guide prostate cancer detection at different serum prostate-specific antigen（PSA）levels.【Methods】Totally 278 patients who underwent a systematic biopsy were collected in our hospital from November 2014 to June 2016. Preoperative tests of PSA， MRI，TRUS were performed in all the included patients. According to the PSA level of 4 ~ 10 ng/mL，10 ~ 20 ng/mL，over 20 ng/mL， 278 cases were divided into three group of A，B，C. Retrospective analysis was performed within the three groups of diagnostic accuracy.【Results】In Group A，the areas under ROC for MRI+TRUS and TRUS were 0.73 and 0.59，respectively（P = 0.02）. In Group B，the areas under ROC for MRI+TRUS and TRUS were 0.68 and 0.56，respectively（P < 0.001）. In Group C，the area under ROC for MRI+TRUS and TRUS were 0.74 and 0.63，respectively（P < 0.001）. There is more significant statistical difference in Group B and C.【Conclusion】MRI combined TRUS has higher diagnostic value in cancer detection than TRUS before biopsy between different PSA levels，which Indicates that MRI combined TRUS is an effective method for the improvement of prostate cancer detection.