Prostate-specific antigen is the most sensitive tumor marker for prostate cancer and is superior to prostate acid phosphatase (PAP) in determining the volume of prostate cancer but less specific than the latter in diagnosing prostate cancer. PSA can also be increased in cases of benign prostatic hyperplasia and inflammation of the prostate. However, PSA is still an important indicator for prostate cancer diagnosis, clinical staging, outcome observation and prognosis. Recent studies have shown that PSA rate, PSA density and PSA range with age have practical significance in clinical application. 1.PSA rate That is, the change of serum PSA concentration was continuously observed, and the PSA rate of prostate cancer was significantly higher than that of prostate hyperplasia and normal group. The normal value is 0.75ng/ml per year, so PSA rate can distinguish between early prostate cancer and prostate hyperplasia. 2. PSA density (PSAD) is the ratio of serum PSA concentration to prostate volume. When the PSA concentration is mildly elevated and the prostate volume is small, it also suggests the presence of prostate cancer; when the prostate volume is elevated, although there is an increase in PSA, it may only be benign prostatic hyperplasia. When a patient’s PSA is at the high limit of normal or mildly elevated, using PSAD can guide the physician in deciding whether to perform a biopsy or follow up prevention. 3. The range of PSA values for each age group The concentration of normal serum PSA increases with age. Combining the age factor and PSA concentration makes it easier to detect prostate cancer early in younger patients.