Causes of renal pelvis cancer mainly include long-term exposure to carcinogenic substances, smoking, analgesic drugs and so on. 1. Long-term exposure to susceptible environment: some industrial raw materials such as rubber and paint contain benzidine and other aromatic amines, which are carcinogenic substances for renal pelvis cancer, long-term exposure will lead to higher possibility of patients suffering from renal pelvis cancer. 2. Smoking: long-term smoking is an important cause of renal pelvis tumor, the incidence rate of smokers is about three times of non-smokers, and its risk rate increases with the length and quantity of smoking. 3. Long-term analgesic drugs: Long-term and heavy use of analgesic drugs, especially finasteride, is a risk factor of renal pelvis cancer. There are many other causes of renal pelvis cancer, such as Balkan nephropathy, urinary tract infection, stones, etc. Early prevention of renal pelvis cancer is recommended, and early treatment is recommended once diagnosed in order to achieve the best treatment effect.