The right scrotum is empty, the inguinal mass is hard and painful to palpation, ultrasound indicates poor blood flow to the testicle, surgical exploration reveals testicular necrosis, which can only be removed Cryptorchidism is a common disease in pediatric urology, and the chance of torsion in pediatric cryptorchidism is many times higher than that of intra-scrotal testicle. The onset is rapid and there are no special clinical symptoms, so it is easy to be misdiagnosed. The possibility of torsion of cryptorchid testis in children is related to many factors: testicular dysplasia, testicular lead too long first, congenital anatomical abnormalities; the spermatic cord in the sphincter cavity of children with cryptorchid testis is longer, the epididymis is separated from the sphincter wall layer, the sphincter cavity is wider, the testis can slide back and forth in the inguinal canal; the cryptorchid testis folds back from the inguinal inguinal subcutaneous ring to beyond the tendon membrane of the external oblique abdominal muscle, which is easily subjected to external force and torsion occurs.