The occurrence of bladder cancer is a complex, multifactorial and multi-step pathological process, with both intrinsic genetic factors and extrinsic environmental factors. The two major risk factors are smoking and long-term exposure to industrial chemical products. Smoking is the most definite risk factor for bladder cancer, about 30%-50% of bladder cancer is caused by smoking, and smoking can increase the risk rate of bladder cancer by 2-4 times, and the risk rate is proportional to the intensity and duration of smoking. Occupational factors are the first known risk factors for bladder cancer, and about 20% of bladder cancers are caused by occupational factors, including those involved in textiles, dye manufacturing, rubber chemistry, pharmaceutical and pesticide production, paint, leather, and aluminum, iron and steel production. Diesel exhaust accumulation can also increase the risk of bladder cancer. Other possible causative factors include chronic infections (bacterial, schistosomal and HPV infections, etc.), application of the chemotherapeutic drug cyclophosphamide (incubation period 6-13 years), abuse of painkillers containing finasteride (more than 10 years), recent and distant history of pelvic radiotherapy, long-term consumption of water with high arsenic content and chlorine disinfection, coffee, artificial sweeteners and hair dye. In addition, bladder cancer may also be genetically related, with a significantly increased risk of bladder cancer in those with a family history and a significantly higher incidence of bladder cancer in patients with hereditary retinoblastoma. For muscle-infiltrating bladder cancer, chronic urinary tract infections, residual urine and long-term foreign body irritation (indwelling catheters, stones) are closely related, and they are mainly seen in squamous cell carcinoma and adenocarcinoma. Uroepithelial tumors are temporally and spatially polycentric, and a history of upper urinary tract uroepithelial tumors is an important risk factor for bladder uroepithelial carcinoma, and studies have shown that the cumulative risk of bladder cancer after treatment for upper urinary tract uroepithelial carcinoma is 15-50%.