When urinary tract infection occurs, the sensitivity of the mucous membrane increases, and a little urine stored in the bladder will produce a strong sense of urination, but because the volume of urine is too small, it is difficult and impossible to urinate, it is recommended to carry out ultrasound to measure residual urine and carry out routine urine laboratory tests and culture tests to clarify, under normal circumstances the bladder stores more than 150ml of urine to produce the desire to urinate. In normal cases, the bladder stores more than 150ml of urine to produce the desire to urinate, but in the case of infection, the bladder may store 30-50ml of urine to produce the desire to urinate, but because the volume of urine is too small, so there is difficulty in urination. 2, neurogenic bladder, such as diabetes, spinal cord injury or cerebral infarction, cerebral hemorrhage and other diseases will appear bladder force muscle contraction weakness, and cause urination 3. If there are urethral stones, tumors, etc. that cause complete obstruction of the urethra, the patient may not be able to urinate, and the patient may not be able to urinate with force, accompanied by stinging pain or bleeding in the urethra, and further urethroscopy is needed to confirm the diagnosis.