Objective To detect the protein expression level of human myeloid cell leukemia 1 (MCL-1) gene in prostate cancer and its effect on the prognosis of prostate cancer. Methods MCL-1 protein expression was detected by immunohistochemistry in 517 cases of prostate cancer tissues and the corresponding adjacent tissues. The correlation was analyzed statistically between the expression level and the prognosis of prostate cancer patients. In addition, after the expression of human MCL-1 protein in prostate cancer cell line was interfered, MTT assay, clone formation assay and TUNEL assay were performed to test the ability of cell proliferation and apoptosis. Results The expression of MCL-1 in prostate cancer was significantly higher than that in adjacent tissues, and the prognosis of patients with MCL-1 high expression was poor. The proliferation and apoptotic resistance of prostate cancer cells significantly decreased after the expression of MCL-1 was knocked down in prostate cancer cells. Conclusion The expression of MCL-1 in prostate cancer tissues was much higher than that in normal prostate tissues, and knockdown of MCL-1 in prostate cancer cells inhibits the proliferation and promotes apoptotsis of prostate cancer cells.