Bladder cancer is the most common malignant tumor of the urinary system, and its death rate is in the first place among the malignant tumors of the urinary system. The size of bladder cancer is not a criterion to judge its early, middle or late stage. Bladder cancer is staged by the depth of tumor infiltration, and the depth of tumor invasion can be judged by enhanced CT of the pelvis, which can be clinically divided into T1 stage, T2 stage, T3 stage and T4 stage. 1. T1 stage: the tumor is confined to the lamina propria of the mucosa and has not reached the muscularis propria. 2. T2 stage: the tumor has broken through the mucosal lamina propria to reach the muscularis propria; if it only invades the superficial muscularis propria, it is T2a stage; if it has invaded the deep muscularis propria, it is T2b stage. 3. T3 stage: the tumor cells have broken through the muscular layer and invaded the plasma membrane layer, at this time, the tumor has reached the advanced stage. 4. T4 stage: the tumor has invaded the neighboring organs and metastasis has occurred. Bladder cancer is the malignant tumor with the highest morbidity and mortality rate in the urinary system, and its most common symptom is intermittent, painless hematuria. Once you find intermittent, painless hematuria and other symptoms, you should seek medical treatment in time for early diagnosis and early treatment.