Total prostate-specific antigen (PSA) is the sum of free and complex PSA in serum; what is not bound to plasma proteins but exists freely is free PSA. Prostate-specific antigen (PSA) is found in the epithelial cells of the prostate ducts and is a glycoprotein secreted by the prostate gland, part of which enters the circulation. The sum of all PSA that enters the circulation is called total prostate-specific antigen (tPSA). Most of the tPSA that enters the bloodstream binds to plasma proteins such as alpha-1 antichymotrypsin and alpha-2 macroglobulin and exists in a bound form called complex PSA (cPSA), and a small portion exists in a free form called free prostate-specific antigen (fPSA). Elevated tPSA can be seen in prostate cancer, prostate hyperplasia, prostate massage, etc. Elevated tPSA, fPSA and decreased fPSA/tPSA suggests the possibility of prostate cancer. If there is any PSA abnormality, it is recommended that the patient should consult the doctor in time and follow the doctor’s instructions for examination and treatment.