Free prostate-specific antigen and prostate-specific antigen are mainly different in concept. Prostate-specific antigen (PSA) is a glycoprotein secreted by the epithelium of the prostate ducts. About 80% of PSA in serum exists in bound form, known as complex PSA (c-PSA), about 20% exists in free form, known as free PSA (f-PSA), and all PSA in serum is known as total PSA (t-PSA). Therefore, the prostate-specific antigen test includes total prostate-specific antigen and free prostate-specific antigen, and free PSA is a type of PSA. Blood t-PSA should be <4 μg/L, f-PSA should be <0.8 μg/L, and f-PSA/t-PSA should be >0.25. Higher-than-normal prostate-specific antigen may indicate the presence of benign diseases such as prostate hyperplasia or malignant tumors such as prostate cancer, or it may be caused by manipulation such as prostate massage, therefore, it is recommended that people with PSA abnormality should consult a specialist in time and follow the doctor’s instructions for further examination and treatment.