Sudden blood in urine is mainly seen in the urinary system stones, urinary system inflammation, urinary system tumors and other reasons. 1. Urinary stones: the symptoms are related to the size of the stones, and there may be no obvious symptoms when the stones are small. When the stone wears down the mucous membrane of the urinary system, blood in the urine will appear suddenly. Stones can be removed by extracorporeal shock wave lithotripsy and surgery. 2. Inflammation of urinary system: such as glomerulonephritis, cryptoglomerulonephritis, chronic glomerulonephritis, blood in urine can also appear suddenly. The treatment of glomerulonephritis is related to the patient’s condition and is usually based on drug treatment. 3. Urinary system tumor: such as malignant tumor of bladder, early no obvious symptoms, when the tumor breaks down and bleeds manifested as blood in urine. Urological malignant tumor patients in the progressive stage may need surgical treatment, radiotherapy, chemotherapy and other ways of treatment. 4. Other causes: blood in urine is also related to systemic coagulation dysfunction and hemophilia, which should be treated for blood diseases. If the patient is not feeling well, he/she should consult the doctor for examination and early treatment.