A protein enzyme called prostate-specific antigen (PSA) exists in the normal prostate gland, and when prostate tissue becomes cancerous, it enters the bloodstream, so serum tests in prostate cancer patients often detect elevated levels of PSA, which is why PSA is also used as a specific marker for prostate tumors. However, an elevated PSA level does not necessarily indicate prostate cancer. Certain diseases such as prostate enlargement, prostate hypertrophy, prostatitis and even tests such as anal examinations and rectal ultrasound biopsies may also cause changes in PSA, so tests for PSA are usually performed a few weeks before or after these tests. Different molecular forms of PSA can be detected in the serum: free PSA (fPSA), compound PSA (cPSA) and total PSA (tPSA). fPSA and cPSA can be used in conjunction with tPSA to differentiate benign prostate disease from prostate cancer, and fPSA/tPSA increases the positive rate of biopsies. For the diagnosis of disease, high levels of PSA often indicate the presence of metastatic lesions. Also, PSA levels correlate with the staging and grading of prostate cancer, which can help doctors understand the severity of the patient’s disease. Continuous monitoring of PSA levels can detect recurrence or metastatic spread at an earlier stage, and a significant increase over a short period of time or a persistent increase over a period of time can indicate the possibility of recurrence. If high levels of PSA are detected after complete prostatectomy, it may indicate localized residual tumor or metastasis. Prostate cancer is a common malignant tumor in Western men, with the second highest incidence of malignant tumors in men. The incidence rate of prostate cancer has been increasing year by year due to the increase of life expectancy and change of diet structure in China. The incidence of prostate cancer increases with age. Since the early symptoms of prostate cancer are not obvious, regular examination of prostate tumor markers plays an important role in the prevention and treatment of prostate cancer. Prostate tumor markers collaborate with imaging and pathological examinations to play an auxiliary diagnostic role. The current recommendations of domestic experts for prostate cancer marker examination are: PSA and rectal finger examination are routinely performed for men over 50 years old with lower urinary tract symptoms, and for the male population with a family history of prostate cancer, regular examination should start from the age of 45. PSA should be performed for men with abnormal rectal examinations, abnormal imaging or clinical symptoms. Only by starting with raising awareness of cancer prevention and fighting against cancer can we plant hope to overcome tumors!