Catheterization can be divided into male catheterization and female catheterization, according to the different body structures of men and women, the operation process is not consistent. 1. Male catheterization: The first step is to disinfect the external urethral opening. The second step is to check whether the urethra is intact, apply lubricant when it is intact, and replace the catheter if it is broken. The third step is to wrap the penis with gauze and then lift the penis with your hand, while the other hand holds the urethra with forceps and feeds it into the urethra. The fourth step is to inject saline into the balloon after seeing urine flow out of the urethra, which serves to fix the urethra. 2. Female catheterization: The first step is to disinfect the perineum from the outside in. The second step is to check whether the urethra and balloon are broken, apply lubricant if they are not broken, and replace the catheter if they are broken. The third step is to sterilize the urethra from the inside out and then insert the catheter into the urethra and push it in again when you see urine coming out. The fourth step is to use a syringe to inject the balloon into the saline to fix the indwelling urinary catheter. In summary, the operation of urinary catheterization should be carried out aseptically by professional doctors or nurses, and the operation should be stopped immediately when the patient becomes uncomfortable.