The most common symptom of bladder tumor is painless hematuria of the naked eye, of course some patients, advanced bladder cancer will have abdominal pain or lower abdominal discomfort symptoms. The most important cause of hematuria is bladder tumor. Initially, bladder cancer occurs in the mucosal layer, and the bladder wall is divided into mucosal, submucosal, muscular and plasma layers in four layers. Generally speaking, bladder tumor may invade the blood vessels of mucosal layer, submucosal layer or muscular layer, causing blood vessel rupture and bleeding. Some patients have mild hematuria, while others have more severe bleeding and may even form clots, causing the patient to have difficulty urinating and passing urine. In this case, the clot may also have to be removed by bladder irrigation, cystoscopy, so this is the most common bladder tumor infiltrating into the blood vessels, causing significant hematuria, which is the main cause.