The male genitalia can be divided into two parts: the external genitalia and the internal genitalia. The former includes scrotum, penis, testes, epididymis and vas deferens; the latter mainly includes prostate gland, seminal vesicle gland and urethral bulb gland, which together perform a series of functions such as sperm production, semen delivery and male sex hormone secretion. When the penis is in a flaccid state, it hangs in front of the perineum, and when stimulated, the penile corpus cavernosum and urethral corpus cavernosum are filled with blood and erect, and can complete sexual intercourse. In the testis, there are mainly spermatogenic tubules and interstitial cells, the former is mainly responsible for producing sperm and the latter secretes androgens. The epididymis contains the epididymal duct, which is the transport duct and storage place for sperm and is also the place to promote sperm maturation. The epididymis has absorption, secretion and concentration functions, providing conditions for sperm storage and maturation. Abnormal function of the epididymis can lead to impaired sperm maturation, resulting in infertility. The vas deferens is connected to the epididymal duct and has the function of transporting sperm. The prostate is the largest accessory gland in the male body and its main function is to secrete prostatic fluid. The prostate gland is very small in size during childhood, but after puberty it begins to increase in size, and generally by the age of 50, it begins to change in size. The normal size of the prostate is about 3.5 cm in diameter left and right, 2.5 cm in diameter front and back, 2.5 cm in diameter top and bottom, and weighs about 20 grams. The prostate fluid is excreted to the urethra through the prostate duct that opens in the urethra, and is an important part of the semen, accounting for about one-third of the total semen, and plays an important role in male fertility; in addition, it can secrete hormones such as prostaglandins; it is also involved in the composition of the internal sphincter of the urethra, which can control urination. The seminal vesicle gland has the role of secreting seminal fluid and storing semen, and is connected to the ejaculatory duct and vas deferens, respectively. The muscles of the prostate and seminal vesicle glands contract during ejaculation, pressing the contents of the vas deferens and seminal vesicle glands into the posterior urethra through the ejaculatory ducts and out of the body.