1.Absolute pointer: only one kidney; or two kidneys with one kidney not functioning well; double kidney tumor; benign tumor of kidney; 2.Relative pointer: chronic diseases such as kidney stone or hypertension and diabetes. 3.Optional pointers: early kidney tumor <4cm; 4.For the current technology level, tumor even more than 7cm can be performed kidney preserving surgery; the pointers for kidney preserving surgery are based on the patient's condition and the doctor's level.