The clear liquid before ejaculation is usually prostate fluid, which is a normal physiological phenomenon. Prostate fluid is mainly the secretion of the prostate gland, but also an important component of semen, or one of the components of seminal plasma in semen, can be secreted before ejaculation, is a normal physiological phenomenon. The protein content is small, mainly acid phosphatase, protein hydrolase, fibrinase, zinc ions, spermine, lipid peptides, and so on, and one of the protein hydrolase and fibrinase has the role of promoting the liquefaction of semen. At the same time, prostate fluid also has the effect of promoting the formation of fertilized eggs, stimulating sperm vitality, maintaining genitourinary hygiene and improving the quality of sex life. Detection of acid phosphatase and citric acid can also assist in determining the function of the prostate gland and the presence of cancer. If there is any abnormality in the prostate fluid, it is necessary to pay attention to it and seek medical treatment in time. To summarize, the clear fluid secreted before ejaculation is generally prostate fluid, and men are advised to correctly recognize semen and prostate fluid.