Prostate cancer is a very important type of male germline tumor. With the aging of our population and the improvement of medical diagnosis technology, the incidence of prostate tumor is gradually increasing. The PSA is the most specific tumor marker for prostate cancer and is a serine protease secreted by prostate epithelial cells. Under normal circumstances, the contents of the PSA-rich prostate follicles are separated from the lymphatic system by a barrier consisting of the endothelial layer, basal cell layer and basement membrane. When a tumor or other lesion disrupts this barrier, the glandular contents can leak into the lymphatic system and subsequently enter the bloodstream, resulting in an increase in peripheral blood PSA levels. Because PSA is a marker for prostate epithelial cells, it is not a marker for prostate cancer. Therefore, in addition to prostate cancer, benign prostate hyperplasia and inflammatory prostate lesions can also increase PSA levels. The PSA level can also be elevated by benign prostatic hyperplasia and inflammatory prostatic lesions. Therefore, when the PSA is elevated, we need to evaluate the patient’s overall condition to rule out prostatitis and mechanical irritation as factors that can elevate the PSA.