Since the results of semen analysis are directly affected by the accuracy of specimen collection, time of abstinence, temperature, acidity and chemical substances, etc., the following issues should be noted during semen collection: 1. Abstinence (including spermatozoa and masturbation) must be observed for 3-5 days before collection of the specimen, but generally not more than 5 days, because if the abstinence time is too long, the vitality of spermatozoa decreases, even though the volume of semen will increase. 2. All ejaculated semen should be collected in a clean, dry glass bottle or test tube. Latex condoms should not be used because they contain silicone oil and talcum powder, which can affect sperm vitality. After the specimen is collected, the number, name, time and date of collection and the number of days of abstinence should be indicated. 3. The specimen should be sent for examination immediately after collection, and the storage time should not exceed 2 hours. The temperature of its storage or transfer is 25-35 degrees Celsius is appropriate. 4, the number of specimen collection: due to the spermatogenesis day to day changes, can not be based on the results of a single examination to make a diagnosis. Generally, it should be checked once every 1~2 weeks. The examination should be carried out 2~3 times in a row. 5, incomplete semen specimens should not be semen analysis.