The testes are the two male gonads that are responsible for the production and storage of sperm, as well as being the main source of male androgens. Testicular cancer is a malignant tumor formed by the cancerous transformation of cells in the testes. It accounts for only 1% of all male carcinoid tumors, but occurs mostly in men aged 15-39 years old, and is the most common malignant tumor in men aged 20-34 years old, the peak of their reproductive years. Like other malignant tumors, the factors leading to testicular cancer are very complex, but the most dangerous of them is cryptorchidism. Cryptorchidism is formed when a male’s testicles fail to descend into the scrotum at birth and are retained in the abdominal cavity. Even with surgical treatment, the chance of malignancy is still 20 times higher than normal; if it is never removed, the chance of malignancy can be more than 50%. This fact shows that being in a higher body temperature for a long time is harmful to the testicles. In addition to healthy lifestyle habits, the most important thing to prevent testicular cancer is to detect testicular abnormalities at an early stage so that early diagnosis and timely treatment can be made. Generally speaking, it takes an average of 3 months from the occurrence of testicular cancer to the lymph node metastasis of the tumor. Meanwhile, it is recommended that every young man should establish a healthy lifestyle concept, such as proper intake of dairy products, quit smoking, reduce alcohol consumption and exercise properly to reduce the risk of testicular cancer. The early clinical symptoms of testicular cancer, like breast cancer, are mainly painless lumps, which can be detected early by means of self-examination. Therefore, it is necessary for all men, especially those aged 15 to 39, to check their scrotum and testicles by themselves once a month. Once a lump or any abnormality is found in the scrotum, they should be alert and go to the urology department in time.