Male urinary catheterization usually refers to male catheterization, and its precautions mainly include preventing retrograde infection of the urinary system, drinking plenty of water, training the function of bladder reflexes, and observing the urine situation. 1. Prevent retrograde infection of the urinary system: (1) Keep the urethral opening clean: male patients should wipe the urethral opening, glans and prepuce with a sterilized cotton ball 1~2 times a day. Promptly wash the anus and perineal skin after defecation. (2) Replacement of urine collection bag: pay attention to observe and empty the urine in the collection bag in time, usually change the collection bag 1~2 times a week, if there is a change in the nature and color of urine, need to be replaced in time. (3) Replacement of urinary catheter: replace the catheter regularly, the frequency of replacement of urinary catheter is usually decided according to the material of catheter, usually replaced once every 1~4 weeks. (2) Drinking more water: During the period of indwelling urinary catheter, if the condition permits, more than 2,000 ml of water should be ingested daily (including oral and intravenous fluids, etc.) to achieve the purpose of flushing the urethra. 3. Train the bladder reflex function: Intermittent clamping can be used. Clamp the catheter and open it once every 3~4 hours to make the bladder fill and empty regularly and promote the recovery of bladder function. 4. Observe the urine situation: if you find cloudy urine, precipitation, crystallization, you should promptly report to the doctor for treatment, and check the urine routine once a week. Male catheterization should be carried out by healthcare personnel, and any discomfort symptoms during indwelling urinary catheter should be reported to the doctor in time.