Any part of the digestive tract can be pushed or squeezed by the retroperitoneal tumor, which can be injured if no attention is paid during the operation. However, the stomach and small intestine are highly mobile, so the chance of being injured during surgery is small. The duodenum, right and left colon and rectum are more likely to be injured, especially the rectum. When separating the tumor from the mesentery, care should be taken not to injure the blood vessels of the mesentery. Once the blood vessels are injured and the blood flow of the intestinal wall is impaired, the corresponding bowel resection and anastomosis should be done. Injury to rectal wall is mostly seen in large pelvic retroperitoneal tumors, where the rectum is displaced by pressure and the tumor occupies the pelvic cavity, and the local exposure is poor, which may injure the rectal wall with little attention. Sometimes the rectum is not found to be injured intraoperatively, and then postoperative intestinal fistula may occur. Therefore, when doing surgery for huge pelvic tumor, we should pay full attention to the local exposure and carefully separate the tumor from the intestinal wall. When we suspect that the intestinal wall may be injured, we can temporarily block the proximal end of the intestinal canal, place a tube from the anus, inject Meridian blue and observe whether there is Meridian blue spillage at the suspected injury. In order to find out whether there is a full-layer injury in the intestinal canal. Timely detection and treatment. A large tumor located in the right upper abdomen can cause significant displacement of the duodenum because of the possibility of injury to the intestinal wall during separation. The blood flow of duodenal wall is relatively poor, so extra care should be taken when repairing after injury, otherwise intestinal fistula will be easily formed, which is a serious complication and should be avoided as much as possible. Retroperitoneal tumors located in the left upper abdomen can sometimes cause significant displacement of the caudal part of the pancreatic body or the spleen. In most cases the tail of the pancreas or the spleen can be separated from the tumor. However, sometimes the spleen can be divided, and the divided spleen can usually be treated with adhesive or sutures after tumor resection, and in some cases splenectomy is required. In some retroperitoneal tumors, especially those recurrent tumors after surgery, the tail of the pancreas and the spleen are difficult to be separated from the tumor, then the tail of the pancreas and the spleen can be considered to be removed together with the tumor. The retroperitoneal tumor can often push and squeeze one kidney, ureter and bladder, especially the ureter can be pushed to a very far place, completely away from the normal anatomical part, which may be injured if not paid attention during the operation. Therefore, a ureteral catheter should be placed preoperatively so that the ureter can be more easily identified intraoperatively. The ureter is always displaced forward and pushed to one side, and when the tumor is large the ureter may be pushed to the opposite side in an arch shape. However, the separation between the tumor envelope and the ureter is often not very difficult. Separation should be performed with minimal damage to the blood supplying the ureter. After freeing a section of ureter, a rubber sheet can be used to pull the ureter and then separate it from the tumor envelope. With careful manipulation, injury to the ureter can usually be avoided. If a huge retroperitoneal tumor located in the pelvis can push and squeeze the bladder, it is often difficult to recognize the ureter entering the bladder triangle. If possible, try to find the ureter proximally first, and then follow it to the bladder triangle to separate it from the tumor. There is a greater chance of the ureter being injured in this situation. Once the ureter is injured, it can be repaired after tumor removal. Ureteral anastomosis is usually performed by placing a pigtail catheter in the lumen of the ureter with the upper end hanging from the renal pelvis and the lower end inserted into the bladder. The two disconnected ends are anastomosed end-to-end. Drainage must be placed. After the operation, local leakage is more in the initial stage and will gradually decrease until it heals, and the cystoscope can usually be used to remove the catheter as a stent from the bladder in 3 to 4 weeks. If the tumor affects the bladder triangle and the bladder wall in the triangle is damaged during surgery, including the removal of the bladder, then a double ureter and bladder anastomosis can be done. If the anastomosis is difficult, uretero-ileal anastomosis, ileostomy is required. Or the ureter can be led directly outside the body for fistula. Retroperitoneal tumors, especially liposarcoma, a significant portion of which is derived from perirenal adipose tissue, are called perirenal liposarcoma. Many retroperitoneal tumors can push the kidney farther away and often the kidney must be removed at the same time. The kidney is one of the most common organs removed in combination with retroperitoneal tumors. We have dealt with several cases of smooth muscle sarcoma of the inferior vena cava in which the tumor had involved the entire right kidney and left renal vein. We performed a complete resection of the inferior vein including the right and left renal veins, and did not perform a reconstructive graft of the inferior vena cava. The preoperative venography confirmed that the inferior vena cava static vein had been completely obstructed. After disconnecting the inferior vena cava and the right kidney during the operation, the urine in the bladder was emptied first, and then the left kidney vein was blocked and tachypnea was injected sedately. 0.5h was observed and 300ml of urine was seen to be discharged. It indicates that although the left kidney can no longer return from the left renal vein, it can return through the established collateral vein and can still urinate normally. The patient’s postoperative renal function was normal. The combined resection and reconstruction of kidney, ureter, bladder and other organs can be handled correctly during the operation. Postoperative complications can also be significantly reduced.