The average length of the female urethra is 3~5cm, so the catheter is usually inserted 4~6cm, and after there is urine outflow, it continues to be inserted for 5~7cm before hitting the water bladder. The female urethra is 3~5cm long on average, with a diameter of 0.6cm, which is shorter, wider and straighter than the male urethra. Therefore, female catheterization, the general catheter inserted 4~6cm, see urine outflow is prompted catheter into the bladder. After the catheter is inserted into the bladder and urine flows out, the catheter is continued to be inserted into the bladder for 5-7cm, about 5ml of water is injected into the catheter to fill the bladder, and the catheter is slowly pulled outward so that the bladder is embedded in the opening of the bladder to ensure that the catheter will not be dislodged. Female catheterization also needs to pay attention to the first release of urine should not be more than 500ml, the urine collection bag should be placed in a position lower than the bladder, and should pay attention to regular replacement of the indwelling catheter. If there is any discomfort, consult a doctor promptly.