Testicular transplantation is used to solve the problem of androgen production after testicular dysfunction, as male characteristics will gradually disappear due to androgen deficiency. Testicular transplantation is mainly used for trauma, testicular torsion and testicular atrophy. 1. Trauma: Due to testicular blood supply malfunction after testicular injury, testicular transplantation in situ or ectopic transplantation can be performed if the testicle has been detached. 2. Testicular torsion: Testicular torsion refers to the twisting of the spermatic cord of the testicle, which will compress the blood vessels and affect the blood supply of the testicle, and may lead to necrosis in severe cases. As the testicle is not able to produce effective androgen, male sexual function and fertility can be restored through testicular transplantation. 3. Testicular atrophy: Due to congenital juxtaposition of testes, epididymitis, abnormal testicular development, etc., the number of parenchymal cells in the testes is reduced, resulting in testicular atrophy. Intra-scrotal transplantation can be done with testes from voluntary donors, but anastomosis of arterial and venous blood vessels is required for survival. Testicular transplantation is delicate and difficult to perform, and there may be poor blood supply to the testis after the surgery, etc. Testicular transplantation is only possible when conditions permit, and it is not widely practiced at present.