The best time to operate for cryptorchidism is within two weeks of age. Cryptorchidism refers to the failure of the testicle to descend normally into the scrotum, including incomplete descent of the testicle and ectopic testicle. Normally, the testicles can complete their descent on their own within three months after birth, and it is possible for the testicles to descend into the scrotum on their own within one week of age. If the testicles fail to descend as expected, surgical treatment is usually recommended between the ages of one week and two weeks, and as much as possible within two weeks of age. This is because surgical treatment within this time period has the least impact on the affected child’s testicles. If the testes are older than two weeks of age, the impact on the testes is relatively greater. Since the environment in the abdominal cavity is somewhat different from that in the scrotum, this may lead to a decrease in the number of spermatogenic cells in the testes, which in turn may cause a decrease in semen quality and may have some impact on fertility. Therefore, parents of boys are advised to pay attention to the growth of their children, and if the testicles have not descended to the scrotum by the age of two, they should promptly take their children to the pediatrician for a clear diagnosis and targeted treatment to avoid delays.