There are two possible clinical conditions for not urinating: First, there is urine in the bladder, which cannot be discharged, and the examination can see that the patient has a bulging bladder area, the patient has a feeling of holding urine, cannot urinate on his own, and urinary retention occurs. The common cause is lower urinary tract obstruction, such as prostatic hyperplasia, urethral stricture, urethral calculi, bladder neck contracture and stenosis in elderly men. In addition, the bladder forced urinary muscle contraction weakness, such as after major pelvic surgery, rectal cancer, radical resection of cervical cancer, hemorrhoid surgery, and neurogenic bladder caused by cerebrovascular accident, long-term diabetes, cerebrospinal cord trauma, etc. Second, there is no urine in the bladder itself, and the patient does not have a feeling of holding, mainly due to renal insufficiency, renal failure or bilateral ureteral stones, causing complete obstruction of the ureter bilaterally and the appearance of non-urination. Therefore, when non-urination occurs, we must first find out whether there is urine in the bladder.