The blood-testis barrier is a special kind of barrier function for men, which refers to a barrier structure between the spermatogenic tubules and capillary blood, which can prevent certain substances from entering the spermatogenic epithelium and maintain the microenvironment for spermatogenesis, and has a certain immune barrier effect on male reproductive function. Among the effects are the following, 1, can form a kind of immune barrier, can not let the body produce anti-sperm antibodies, in order to avoid the occurrence of autoimmune reactions. 2, can prevent harmful substances from interfering with the occurrence of sperm, and damage the formed sperm. 3, to create a good environment for the production of sperm, to ensure the occurrence of sperm, there is a normal microenvironment, if the loss of the blood testicular barrier, it will produce a certain If the blood testicular barrier is lost, a certain autoimmune reaction will occur, which will greatly reduce the activity function of sperm.