Renal tumors are more common in the genitourinary system, and the incidence rate in China is second only to bladder tumors. Renal tumors are mostly malignant, and the vast majority of adult renal tumors are nephrocalcinomas, with fewer renal pelvic carcinomas. Among pediatric malignant tumors, nephroblastoma accounts for more than 20%. The most common of the benign tumors is renal vascular smooth muscle lipoma, also known as renal malignant tumor. Renal tumors usually have the following Clinical manifestations: 1. About 50% of patients with renal cancer do not have any clinical symptoms and are only found during physical examination. 2.Common symptoms are hematuria and painful mass (renal cancer triad), which is the late stage manifestation of renal cancer. 3.Systemic symptoms include fever, hypertension, rapid blood sedimentation, weight loss, erythrocytosis, hypercalcemia and varicocele of the spermatic cord which can not be disappeared in male patients in lying position. Wasting, anemia, and weakness are often late symptoms. In addition, a few patients may seek medical attention with metastatic symptoms such as pathologic fractures, nerve palsy or hemoptysis. The following clinical auxiliary examinations can help to diagnose renal tumor: 1. Ultrasonography: early renal cancer of 1cm in the kidney can be detected. Kidney cancer is often characterized by a solid mass with low to medium echogenicity and uneven internal echogenicity. A few of them can be characterized as medium-high echogenicity, which is not easy to be distinguished from renal malformation tumor. This examination is simple and easy to perform, and can be the first choice for routine physical examination. 2, X-ray examination: abdominal plain film can see the renal shape increase, the outline change, and occasionally can see the tumor calcification. Intravenous urography can show irregular deformation, elongation, displacement or filling defects of renal calyx and renal pelvis due to extrusion by tumor. 3. CT scan: It is of great value in the diagnosis of renal tumor and can detect early renal cancer. When scanning, renal cancer often shows middle or low density inhomogeneous mass, and the degree of enhancement of the tumor is not as much as that of normal renal parenchyma. It can also show whether there are lymph node metastasis, adjacent tissues and renal veins, and whether there is cancer thrombus in vena cava. 4. Magnetic resonance imaging (MRI): because of strong signal contrast, it can obtain better results in the examination of renal tumor, metastasis, invasion of neighboring tissues and organs, and cancer thrombus in renal vein and inferior vena cava. 5.Renal arteriography: it can show pathological blood vessels, arteriovenous fistulae, vascular pools and increased peripheral blood vessels in the tumor. It is helpful for the diagnosis of small renal cancer with diameter less than 3cm.