Kidney cancer is a common malignant tumor in urology. More than 200,000 people worldwide are diagnosed with kidney cancer each year, while more than 100,000 people die from this disease each year. The treatment of kidney cancer is mainly surgical resection, while radiation therapy, chemotherapy and immunotherapy are not effective. For decades, radical nephrectomy has been the most basic treatment for kidney cancer. In recent years, there is an international trend from radical nephrectomy to kidney unit preservation surgery, but under the propaganda of some hospitals and some media, this trend has intensified, and many kidney cancer patients have asked for kidney preservation surgery after admission, and this is also taken as an important criterion to measure the level of hospitals. However, everything has its two sides, and kidney unit preservation surgery is not a life-saver for all kidney cancer patients. Successful kidney unit preservation surgery has the same tumor control effect and the advantage of preserving more functional kidney units compared with traditional radical kidney cancer surgery, so it has become a hot spot in the current research of kidney cancer surgery, but this surgery requires high technical content and has very strict surgical indications, in other words, not every kidney cancer patient can preserve the kidney. In other words, not every kidney cancer patient can be preserved. It is generally believed that only tumors less than 4 cm in diameter and confined to the edge or upper and lower poles of the kidney are worth preserving the kidney, while there are many patients with isolated kidney cancer, double kidney cancer, kidney cancer on one side with severe renal insufficiency, and kidney cancer on one side with previous kidney disease on the opposite side. The surgery not only can completely remove the tumor lesion as traditional radical surgery, but also can preserve the normal renal parenchymal unit to the maximum extent, which can guarantee the kidney function reserve and add a guarantee for the future health of the patient. However, for those kidney cancer patients with large tumors close to the central part, it is not worthwhile to take the risk of residual tumors after surgery in order to achieve the goal of kidney preservation, and it is not advisable. Therefore, radical kidney cancer surgery to preserve kidney units is not a universal surgery. Whether to preserve kidney or not after kidney cancer must be decided carefully by experienced surgeons, taking into account all factors, and followed up closely after surgery, so as not to bury the root of the disaster by rash and arbitrary decision.