Objective · To investigate the value of prostate volume, free prostate-specific antigen (f-PSA)/ total PSA (t-PSA) ratio, PSA density (PSAD), colour Doppler ultrasound and contrast-enhanced transrectal ultrasonography (CETRUS) in patients with PSA level of 4–10 ng/mL. Methods · Retrospective analysis were performed in 119 patients with serum prostate-specific antigen level of 4–10 ng/mL who suspected prostate cancer in Pudong Gongli Hospital Jan 2015 to Jul 2018. All patients received TRUS-guided rectal (8+n)-core method biopsy. According to the result of puncture, the prostate cancer detection rate in patients with different prostate volumes, f-PSA/t-PSA ratios, PSADs, colour Doppler blood flow signals and CETRUS examination results. Results · The detection rate of prostate cancer in biopsies was 56.3% (67/119). The incidence of benign prostatic hyperplasia was 43.7% (52/119). The detection rate of prostate cancer in patients with f-PSA/t-PSA ratio ≤0.15 was higher than that with f-PSA/t-PSA ratio>0.15 (73.6% vs 42.4%, P0.001). The detection rate of prostate cancer in the patients with PSAD>0.2 μg/L was higher than PSAD ≤0.2 μg/L（69.8% vs 48.7%, P0.026). The detection rate of prostate cancer in the patients with positive CETRUS results was higher than that with negative CETRUS results (72.4% vs 41.0%，P0.001). Conclusion · The f-PSA/t-PSA ratio, PSAD and CETRUS examination results have important clinical significance for diagnosis of prostate cancer in patients with serum PSA level of 4–10 ng/mL.