Semen examination is a very important test in the process of diagnosis and treatment of male infertility, and is an important basis for evaluating a man’s fertility. It includes semen collection methods, semen physical testing, objective sperm viability. Viability measurement and sperm morphology observation and other aspects. (1) Semen specimen collection: the collection of specimens should be abstained from sex for 3-7 days. Generally in the laboratory to take masturbation method to take semen, all collected into a clean glass container, do not use condoms and plastic bottles, the specimen should be kept warm and sent for examination within 30 minutes. (2) Semen analysis: ① Semen volume: ≥2ml, <7ml. ② PH value: 7.2～7.8. ③ Sperm density: ≥20×106/ml. if it is lower than 20×106/ml, the fertility will be reduced. ④ Sperm viability ≥60%. ⑤ Mobility: ≥50% spermatozoa with forward motion or ≥25% spermatozoa rapidly advancing in a straight line within 60 min after specimen collection. (6) Morphology: ≥ 50% of spermatozoa with normal morphology. (7) Leukocytes: ≤1×106/ml. (8) Liquefaction time: <60min. (9) Mucus consistency: mucus filament length less than 2cm is normal.