The operation procedure of urinary catheterization is the preparation of articles and personnel, standardized catheterization operation. 1. Preparation of articles and personnel: medical personnel wash hands, wear masks, check whether the articles are complete and within the validity period, such as disposable catheterization kit, urine bag, saline, disinfection articles and so on. Before the operation, they should understand the patient’s condition and inform the necessity of urinary catheterization. Ensure that the operating environment is comfortable and protect the privacy of the patient. 2. Standardized operation: patients take the supine position, legs apart, expose the vulva, strictly disinfect the towel, check whether the catheter is intact and lubricate it with sterile paraffin oil or saline, male patients use the left hand to lift up the penis to make an angle of about 60 degrees with the abdominal wall (female patients use the left hand to separate and fix the labia minora), expose the urethral orifice, and disinfect it with iodine. Male patients right hand with vascular clamp or handheld catheter inserted into the urethra 18 ~ 20 cm (female patients inserted into the urethral orifice 4 ~ 6 cm), see the urine outflow and then inserted 1 ~ 2 cm, in the catheter balloon injected with saline 10 ml, catheter external drainage bag and fixed. After catheterization need to explain to the patient precautions, indwelling catheterization catheter to keep open, drain tube below the bladder position, to prevent pulling the catheter, keep the perineum clean, drink more water. Urinary catheterization needs to go to the hospital by the physician or nurse standardized operation, in order to avoid adverse situations.