Semen refers to the jelly-like fluid that is discharged from the urethra by a male or male animal during seminal emission. Semen is composed of spermatozoa produced by the testes and seminal plasma. 90% of semen is seminal plasma, which includes sperm secretions and secretions from genital duct glands such as the epididymis, prostate, seminal vesicles, and urethral accessory glands. Seminal plasma contains large amounts of water, protein, fructose, inorganic salts, peptides and prostaglandins, which can provide sperm with nutrition and ejaculatory energy. The normal semen volume is 2-5ml/time. Semen volume >5ml with thin texture and low sperm count is mostly considered too much semen; if the semen volume is <1ml, it is too little semen, which may lead to infertility. Human normal semen contains coagulation factors secreted from the seminal vesicles and liquefaction factors secreted from the prostate gland, so semen can be thick and jelly-like when it is first discharged, which facilitates the retention of semen in the female vagina. The semen usually starts to liquefy in the vagina in 5-10 min, and can be completely liquefied and liquid in 20-40 min, and sperm activity is then active. If the discharged semen does not liquefy for more than 60 min and is always in the form of jelly or clumps, the sperm will lose its normal swimming power. Even if the total number of sperm, density, normal morphology and activity rate are normal, sperm transport difficulties make it difficult for the woman to conceive, and this factor is also one of the causes of male infertility, which needs to be treated in time.