To determine whether a kidney tumor is benign or malignant mainly depends on pathological examination, which is the gold standard for determining benign or malignant. There is no way to determine whether a tumor is benign or malignant by imaging examination, which can only provide a reference. For kidney tumor, if it is relatively small, we can directly do radical surgical resection, after surgical resection, if we find cancer cells in the tumor tissue, we can diagnose malignant tumor of kidney. Most of the malignant tumors of the kidney are clear cell carcinoma of the kidney. If there is no way to remove the tumor by radical surgery, we can do a biopsy of the tumor. If cancer cells are found in the biopsy tissue, it is possible to confirm that the kidney tumor is malignant, i.e. kidney cancer. If radical surgery is not available, neoadjuvant therapy can be done first, and radical surgery can be done after the tumor shrinks.