The traditional surgical procedure for the treatment of kidney cancer is radical nephrectomy, which requires the removal of the entire kidney as well as the perirenal fatty tissue and adrenal glands, and has been considered the standard procedure for the treatment of kidney cancer for many years. Nephron-Sparing Surgery (NSS) is a revolutionary advancement in kidney surgery and has received increasing attention in the treatment of kidney cancer in recent years. With the improvement of medical imaging technology, the improvement of surgical concept and technology, the new understanding of biological characteristics of kidney cancer and the increase of early detection cases, the clinical application of NSS has gradually increased. Traditional radical nephrectomy has its inherent limitations. First, there is a risk of bilateral development of kidney cancer, which has a 4% chance of occurring. If nephrectomy has been performed for kidney cancer and the opposite kidney also develops kidney cancer, it will be very difficult to treat, and if nephrectomy is performed again, the patient will definitely be dependent on dialysis for life. Secondly, many very common diseases, such as hypertension and diabetes, have potential harm to kidney function, which will undoubtedly increase the risk of kidney failure after nephrectomy. Furthermore, clinically, we often encounter some very small kidney tumors (less than 2cm or even 1cm), for these small tumors, it is difficult to determine the benignity and malignancy by imaging, therefore, there is a dilemma in treatment: if we choose to observe, the malignant tumor may cause delay and progress; if we perform nephrectomy, the postoperative pathology confirms that it is a benign tumor, which is, from a certain point of view, an overtreatment, and it is difficult for patients to Acceptance. NSS includes Partial Nephrectomy (PN), wedge nephrectomy and tumor exenteration, the biggest advantage of NSS is that it can preserve as many functional kidney units as possible to protect kidney function. Many clinicians worry that NSS treatment for kidney cancer will lead to higher recurrence rate and shorter survival. However, many clinical studies have confirmed that for early stage limited renal cancer, the survival rate after NSS is comparable to radical nephrectomy, and the 5-year cancer-specific survival rate is 88%-98%. Moreover, several recent publications have reported that the overall survival rate of kidney cancer patients undergoing NSS is better than that of patients undergoing radical nephrectomy, due to the significantly reduced chance of cardiovascular disease and renal impairment in patients after NSS compared with nephrectomy. Moreover, for small tumors that are not well characterized by imaging, NSS is the most reasonable choice to remove the tumor while preserving the kidney, avoiding both delay (pathology is malignant) and overtreatment (pathology is benign). Despite its many advantages, NSS has not been widely performed in clinical practice due to the relative difficulty of the procedure itself and clinicians’ concerns about tumor residual, local recurrence and complications. In China, there are more than 100,000 newly detected kidney tumors less than 4 cm in diameter in a year, and most hospitals in China still use nephrectomy for such small tumors, so NSS is urgently needed in China. The Department of Urological Oncology of our hospital is the first one to carry out kidney unit preserving surgery for kidney cancer in China, and moreover, it has achieved very good treatment results. So, what kind of kidney cancer is suitable for NSS, and the indications for NSS are divided into absolute indications, relative indications and elective indications. Bilateral kidney cancer, isolated kidney cancer (including those after contralateral nephrectomy and congenital) is the absolute indication for NSS. One-sided renal cancer with contralateral renal dysplasia or disorders potentially affecting renal function such as chronic glomerulonephritis, diabetes mellitus, hypertension, etc. are relative indications. There is no specific limitation on tumor size for NSS indications and relative indications. The hot topic of current research is how to limit the size of tumor for selective indications. The traditional view is that the selective indication for NSS is renal tumors ≤4 cm in diameter (stage T1a), and this view is widely accepted. However, many recent reports have shown that NSS is an equally effective and acceptable surgical procedure in tumors of 4-7 cm in diameter. In view of this, the European Association of Urology (EAU) Guidelines for the Management of Renal Cell Carcinoma also state that NSS can be performed electively for renal cancers 4-7 cm in diameter (stage T1b). In our clinical experience, tumor size is not the only criterion for elective indications, but the location of the tumor is very If the tumor is located in the upper or lower pole, with convex growth and easy to resect, even if it is larger than 4 cm, NSS can be performed selectively. Renal cancer does not have a true histological envelope, but often has a pseudo-envelope composed of compressed renal parenchyma and fibrous tissue. Usually, surgeons use the pseudo-envelope as a marker to determine the extent of surgical resection. Traditionally, the surgical margin for NSS is 10 mm or more of renal parenchyma outside the pseudoperitoneum. 10 mm is a safe margin, but it may also result in the loss of many functional renal units, and there is a great deal of controversy regarding the extent of the margin. In recent years, many studies have shown that a 5-mm margin can achieve the same treatment results without increasing the recurrence rate, and some scholars even believe that extraperitoneal resection (i.e., a 0-mm margin) is safe enough. In response to this hot issue, our urological oncology department has conducted a special scientific study, and the preliminary conclusion is that, in general, a 4-mm margin should be available to ensure safe tumor removal. In addition to tumor size and location, the extent of tumor cutting margin should be combined with the degree of pseudo-envelope integrity, CT and other imaging examinations to estimate malignancy and other factors to determine and select an individualized cutting margin range. It is generally believed that NSS has more complications than radical nephrectomy. The main ones are bleeding, urinary leakage, and acute renal function decay. Nevertheless, with the advancement of surgical techniques and the update of instruments and hemostatic materials, NSS has become a relatively safe procedure. None of the NSS we performed had serious complications, and none of the cases have recurred since the follow-up, achieving good treatment results.