Renal cancer is a malignant tumor originating from the urinary tubular epithelial system of the renal parenchyma. The full academic term is renal cell carcinoma, also known as renal adenocarcinoma, or simply renal cancer. It includes various subtypes of renal cell carcinoma originating from different parts of the urinary tubules, but does not include tumors originating from the renal interstitium and renal pelvis tumors. As early as 1883, German pathologist Grawitz proposed the theory that renal cancer is the origin of adrenal tissue remaining in the kidney based on the morphology of cancer cells similar to adrenal cells under the microscope, therefore, renal cancer was called Grawitz tumor or adrenal-like tumor in the books before China’s reform and opening up. It was not until 1960 that Oberling proposed that renal cancer originated from the proximal tubule of the kidney based on the observation of electron microscope, which corrected this mistake. With the increase of people’s health awareness and the development of medical imaging technology, more and more patients with early stage kidney cancer are detected during health checkups. Radical nephrectomy has been the standard procedure for kidney cancer. In recent years, most evidence-based medical evidence shows that the efficacy of kidney unit preservation surgery is almost indistinguishable from radical nephrectomy, and the 5-year tumor-free survival rate after surgery is close. Then, which kidney cancer patients are suitable for kidney preserving surgery? The indications are mainly as follows: 1. kidney cancer of isolated kidney (only one kidney), kidney cancer of both kidneys, kidney cancer with no function of the contralateral kidney or function that cannot be compensated. 2. Patients with kidney cancer suffering from diseases that potentially threaten kidney function (such as hypertension, diabetes, systemic lupus erythematosus, chronic nephritis or pyelonephritis, renal vascular lesions, etc.) and patients with kidney cancer with certain benign diseases (such as kidney stones) in the contralateral kidney, although the total kidney function of the patient is normal before surgery, after removal of one kidney, the above diseases may cause renal function damage to occur renal insufficiency or Uremia. 3. Patients with early clinical stage, tumor diameter ≤4cm, tumor located in the periphery of kidney, single asymptomatic kidney cancer and normal kidney function on the opposite side can choose to perform kidney unit preservation surgery.