According to the different purposes of chemotherapy, it can be divided into three types: i. Neoadjuvant chemotherapy It refers to chemotherapy applied before surgery, and its purpose is mainly to control local lesions, make the tumor down-stage, reduce the difficulty of surgery and eliminate micro-metastases, and improve the long-term survival rate after surgery. For patients with T2~T4a stage who can be operated, neoadjuvant chemotherapy is feasible before surgery. The course of neoadjuvant chemotherapy is not clearly defined, and generally 3~4 cycles are used. Second, adjuvant chemotherapy refers to chemotherapy applied after surgery to delay disease progression and prevent recurrence. The results of various studies on adjuvant chemotherapy are inconclusive due to small sample size, statistical and methodological confusion. Patients with high risk factors for recurrence and metastasis may benefit from adjuvant chemotherapy. Chemotherapy for metastatic bladder cancer Metastatic bladder cancer should be routinely treated with systemic chemotherapy, especially in patients with unresectable, diffuse metastases. Systemic chemotherapy can also be administered to patients in poor health who are not suitable or willing to undergo total cystectomy. The overall efficiency is 40-75%.