The liquefaction time of semen is an item in the routine examination of male semen, which is an indicator of semen quality, because normal semen is viscous and will solidify rapidly when ejaculated outside the body, and gradually turn into a liquid fluid within 20 minutes, which is called semen liquefaction, mainly because there are many kinds of enzymes in semen that can break down proteins, so the process of semen liquefaction is also the hydrolysis of proteins in semen. The process of semen liquefaction is also the hydrolysis of proteins in semen. The medical significance lies in the fact that semen contains a large number of sperm, but sperm cannot move freely in sticky, solid semen, while sperm gain the ability to move freely after the semen is liquefied and can swim quickly in the female reproductive tract to find an egg for conception. In male infertility, one of the causes is the lack of semen liquefaction.