Objective: To explore the diagnostic value of free prostate-specific antigen/prostate-specific antigen density (FPSA/PSAD) combined free/total prostate-specific antigen ratio [(F/T)]/PSAD for elderly patients with prostate cancer. Methods: Elderly male patients who underwent systematic prostate biopsy were selected as the research subjects, including 312 patients with benign prostatic hyperplasia and 175 patients with prostate cancer. The levels of serum PSA, TPSA and FPSA in each group were detected by chemiluminescence assay. The changes of TPSA, FPSA, F/T, PSAD, FPSA/PSAD and (F/T)/ PSAD between the prostate cancer group and the benign prostatic hyperplasia group were compared. The ROC curve was used to analyze the diagnostic value of each index of TPSA, FPSA, F/T, PSAD, FPSA/PSAD and (F/T)/PSAD for prostate cancer. The ROC curve was used to compare the diagnostic value of FPSA/PSAD and (F/T)/PSAD alone and combined detection of prostate cancer. Results: There were significant differences in TPSA, FPSA, PV, F/T, PSAD, FPSA/PSAD and (F/T)/PSAD between the two groups (P <0.05). The ROC curve results showed that the AUC of FPSA/PSAD and (F/T)/PSAD in detecting prostate cancer was higher than that of F/T, TPSA, FPSA and PSAD (P<0.05). (F/T)/PSAD, FPSA/PSAD, and their combined detection of prostate cancer all had good diagnostic value for prostate cancer (P<0.05). The AUC value of (F/ T)/PSAD combined with FPSA/PSAD for the detection of prostate cancer was greater than that of each index detected separately (P<0.05). Its diagnostic cutoff value was 0.402 ng/ml, the sensitivity was 82.9%, and the specificity was 79.8%. Conclusion: The combined detection of (F/T)/PSAD and FPSA/PSAD can improve the diagnostic efficiency of prostate cancer in the elderly.