A man’s sexual function may diminish, mainly related to ageing, excessive life pressure, mental and psychological factors, and reproductive system infections. 1. Ageing: As a man grows older, his libido may gradually decrease and his sexual function will gradually be low, which is a normal physiological feature. 2. Excessive life pressure: If a man lives under too much pressure, works under too much pressure or has a bad relationship between husband and wife, it may lead to a man having no desire for sex and a significant decrease in sexual function. 3. Psychological factors: when a man is in long-term tension, anxiety, depression, may affect the normal sexual function, over time will lead to men with reduced sexual function. 4. Reproductive system infections: If a man suffers from prostatitis, penile spongiform encephalitis, urethritis and other infectious diseases of the reproductive system, it is easy to lead to the occurrence of men’s sexual dysfunction. Men in the usual good habits, quit smoking and drinking, avoid masturbation, the frequency of sex should be moderate, and to adhere to the appropriate physical exercise, can improve the sex life, delay the decline in sexual function.