The main postoperative complications of kidney preservation surgery include bleeding and urinary leakage. Kidney is a very rich blood supply organ, about 1200ml of blood entering bilateral kidneys every minute accounts for 20%-25% of the bleeding volume of heart transfusion. When we do kidney preservation surgery, the broken ends of blood vessels can often be seen on the trauma of the kidney after removing the tumor, and these broken ends of blood vessels are needed to be tightly sutured when the kidney is sutured. However, even so, about 3% of patients will still have complications like bleeding after surgery. The smaller the tumor, the further away from the hilar vessels the less likely it is to bleed; conversely, the larger the tumor, the closer to the hilar vessels the more likely it is to bleed. Secondary bleeding often manifests as hematuria, large amount of fresh blood in the drainage tube or abdominal distension and back distension. Some minor bleeding can heal spontaneously by lying down and braking, but some recurrent or severe bleeding requires intervention to stop the bleeding, or even removal of the kidney in more severe cases (the chances are very small). Regarding urine leakage, first we need to understand the structure of the kidneys. The kidney produces urine, which passes through the calyces and pelvis and then flows through the ureter to the bladder. When we do kidney preservation surgery, sometimes the calyces and/or pelvis are cut due to the deep location or large size of the tumor. Of course the cut calyces and/or pelvis will be tightly sutured when the kidney is sutured, but in some cases with larger breaks there will be a complication like leakage of urine. Once leakage occurs, the leaking urine needs to be drained outside the body, sometimes with a drainage tube for several months to heal; sometimes an internal drainage tube (double J tube) needs to be placed via cystoscopy; and in severe cases, the kidney needs to be removed (the chances are very small). As a patient, you need to look at the complications rationally and do not give up kidney preservation surgery because of the risk of complications, after all, the chance of the above complications is not high; however, you should not be blindly optimistic that such a small chance will definitely not happen to me, because the chance refers to the whole patient population, for a single patient complications only appear or not appear two possibilities.