The operation of urinary catheterization can be roughly divided into several operations, such as pre-operation preparation, cleaning the vulva, disinfecting the vulva, and inserting the urinary catheter. 1. Pre-operation preparation: the operation should be prepared with a treatment tray, iodophor, cotton swabs, disposable catheterization kits, catheter clips, adhesive tape and other items. Let the patient lie on his back, with both legs flexed and knees adducted, and a therapeutic towel under the buttocks to fully expose the urethra. The operator should check the information with the patient, explain the purpose of the operation, and obtain the patient’s trust and cooperation. 2. Clean the vulva: the operator will place the disinfectant tray and the dirt tray next to the patient’s vulva, wear gloves with the left hand, and use tweezers with the right hand to pick up the iodine-vapor cotton balls, and disinfect the vulva from the outside to the inside and from the top to the bottom. The order of cleansing for females is mons pubis, labia majora, labia minora, urethra, urethra to anus. For men, the order is scrotum, penis, and finally, hold the penis with the left hand, turn the foreskin over and disinfect the glans. 3. Disinfect the vulva: open the catheterization kit, wear sterile gloves and squeeze out the iodophor cotton ball. Disinfection of male, the left hand with gauze holding the penis, the right hand clip the povidone-iodine from the urethra rotating outward disinfection of the penis 2-3 times; female disinfection order: urethral orifice, both sides of the labia minora, urethral orifice, disinfection 2-3 times. Disinfection is completed after laying a sterile towel, revealing the urethral orifice. 4. Insert the urinary catheter: first lubricate the catheter with sterile paraffin oil, clip the end of the catheter, place the end in the sterile treatment tray, and slowly insert the front end of the catheter into the opening of the urethra with tweezers. The depth of insertion of the catheter is about 15-20 cm for men and 6-8 cm for women. For patients who need to insert a urinary catheter, they should go to a regular hospital and be operated by a professional physician, and should not operate the insertion of a urinary catheter on their own.