1. Hernia recurrence. Domestic literature reports that the recurrence rate of pediatric hernia after surgery is about 1.0%-2.5%, and the reasons for recurrence are as follows: ① Failure to ligate the hernia sac at the high hernia neck, and later recurrence due to crying and increased abdominal pressure in children. (ii) Tearing of the hernia sac and incomplete ligation. The younger the child, the thinner the wall of the hernia sac, especially in infants with incarcerated hernia, the more edematous and fragile the tissues are and the easier it is to split and tear. At this time, if the hernia sac neck is ligated without lifting the entire perimeter of the hernia sac wall, a small defect (mostly the posterior wall of the hernia sac) is often left behind, which is an important cause of early hernia recurrence. ③The hernia sac is not firmly ligated and the knot is loosened. ④The inner ring opening is large, and there are obvious defects in the inguinal canal wall and transverse abdominal fascia, and the above is not treated with repair, and only high ligation of the hernia sac is performed. 2.Bladder injury. Bladder injury is a serious error in pediatric inguinal hernia surgery. The reasons for this are: ① The bladder is filled and protrudes into the inguinal canal without urination before surgery. (2) Injury by mistakenly stripping the bladder as a hernia sac. ③The hernia sac is small and not easy to find, so the bladder is blindly searched deeper and as a result, the bladder is raised and incised without careful identification. ④Misdiagnosis of bladder slip hernia, mistaking the bladder wall for the hernia sac, and performing bladder wall ligation and partial resection. ⑤ Incorrect positioning of the incision, poor intraoperative exposure, failure to find the outer or inner ring, allowing the bladder to be pulled and displaced, and mistaking the bladder wall for a hernia sac. The key to prevention is to routinely empty the bladder before surgery, to select the incision accurately, to recognize the diagnosis and anatomy of a bladder slip hernia, and to carefully identify the hernia sac. 3. Scrotal hematoma. Most of them are caused by rough surgery, tearing of small vessels, large bleeding from the stripping wound and bleeding from the distal end of the transverse hernia sac without careful hemostasis. Intraoperative separation of the hernia sac should be minimal and all bleeding points should be carefully ligated. Surgery should avoid blind separation by mistake into the scrotum or pulling out the testicles. The scrotal hematoma can be absorbed naturally without special treatment. If the hematoma is progressively enlarged and painful, the incision should be opened to remove the hematoma, stop bleeding and drainage. 4. Ischemic orchitis. The main causes are vascular injury due to excessive dissection of the spermatic cord, or too tight suture of the inguinal ring, which affects the blood flow of the testis, inguinal hernia or large hematoma causing venous congestion and impaired reflux. Take care not to peel off the spermatic cord too much during the surgery and damage the blood vessels, and the main preventive measure is to stop the bleeding thoroughly to avoid hematoma. 5. Testicular displacement. Testicular displacement, also known as cryptorchidism of medical origin. It is mostly caused by inadvertently pulling the testicle out of the scrotum during surgery and failing to put the testicle back into the normal position of the scrotum after surgery, or paying attention to not sewing the spermatic cord on during the reconstruction of the external ring. After the operation, take care to send the testis to the bottom of the scrotum and pull it 1-2 times to make the testis and spermatic cord in the normal position. 6. Complications related to laparoscopic surgery. Complications associated with laparoscopic surgery, such as pneumatization or fluid accumulation in the hernia sac, foreign body sensation in the ligature, hematoma at the poke hole, extraperitoneal emphysema and umbilical poke hole omental hernia, are related to the operator’s unskilled operation, inaccurate judgment, too fast removal of the puncture cannula and violent crying of the child.