Objective To investigate the effect of epristeride on 5-alpha-reductase activity and androgen receptor levels in prostate tissue. Methods Forty patients with benign prostate hyperplasia were randomly divided into the trial group and the control group with 20 in each group. Patients in the trial group were administered oral epristeride and terazosin, while those in the control group were given just terazosin. All patients underwent trans-urethral resection of the prostate after two weeks, and then the 40 samples of prostate were tested immunohistochemically for 5-alpha-reductase activities and androgen receptor levels. Results The 5-alpha-reductase in prostate tissue was not stained or lightly stained in the trial group, while it was heavily stained in the control group. The androgen receptor in prostate tissue was heavily stained in both groups. Conclusion Oral epristeride can inhibit the activity of 5-alpha-redutase in prostate tissue, but it has no obvious effect on the androgen receptor level in prostate tissue.