Semen is composed of spermatozoa and seminal plasma. Spermatozoa are differentiated and developed from the spermatogonia in the spermatogenic tubules of the testes. Mature spermatozoa reach the ejaculatory ducts by the epididymis and vas deferens and are temporarily stored in the seminal vesicles. When ejaculation occurs, a large amount of seminal vesicle fluid, prostate fluid, urethral bulb gland fluid and spermatozoa are mixed, which is collectively called seminal fluid. A healthy adult male ejaculates about 2-6 ml of semen each time. Too little or too much semen is abnormal. Clinically, if semen is not ejaculated for several days and the volume of semen is less than 1.5 ml, it is considered too little semen. After a man excretes semen, semen usually takes 1~2 days of replenishment to return to normal, so those who have frequent sexual intercourse or masturbation will have relatively less semen volume each time, but it can return to normal after a period of time and cannot be considered as too little semen. When the volume of semen excreted at one time exceeds 8 ml, it is called excessive semen, which is a non-physiological phenomenon, mostly caused by genitourinary tract infection and pituitary gonadotropin hypersecretion. Genitourinary infections commonly include prostatitis and vesiculitis. For example, seminal vesiculitis is more common in young adult men and is mostly caused by pathogens such as Escherichia coli, Klebsiella, Aspergillus and Pseudomonas infections. When there are infections in the organs adjacent to the seminal vesicles, such as the prostate, posterior urethra and colon, or when congestion of the prostate or seminal vesicles occurs in some cases, germs can easily take advantage of the situation and induce seminal vesiculitis. Excessive semen is essentially caused by excessive secretion or exudation of seminal plasma, while the total number of sperm does not change, which naturally causes a decrease in the concentration of sperm in semen, thus reducing the chances of conception. Excess seminal plasma secretion can also interfere with the activity and function of sperm due to pathological factors such as inflammation. In addition, excessive semen volume can cause the loss of semen with large numbers of sperm from the vagina, thereby reducing the chances of conception. Therefore, most patients with excessive semen are clinically seen for fertility problems. Clinically, we treat patients with excessive semen for the cause. The first thing to look for is the presence of infection in the genitourinary system. Clinical examinations and tests mainly include ultrasound, bacterial culture, semen mycoplasma and chlamydia tests, etc. If the test results are positive then targeted anti-infective and symptomatic supportive treatment is given. If infection is ruled out and sperm viability is acceptable, then in order to solve the fertility problem, the woman can use pillows on her buttocks and elevate her position after sex to prevent the semen from flowing out; she can also use a cervical cap to improve the chances of conception. If the above fails or if sperm viability is poor, the sperm can be treated in vitro, upstream, etc., and then artificial insemination (IUI) can be performed depending on the sperm viability and concentration. If sperm viability is still poor and concentration is still low, IVF can be done by intracytoplasmic single sperm injection (ICSI). In conclusion, excessive semen is one of the common diseases in male medicine, which has a certain impact on male fertility, especially for men of childbearing age.