Female catheters are inserted into the bladder through the urethra. Female catheterization is to insert the catheter into the bladder through the urethra to drain the urine. The external urethral opening of the female is located above the vagina, when inserting the catheter, it is necessary to routinely disinfect the female vulva, separate the labia minora, find the external urethral opening, and then the catheter is entered from the external urethral opening. After slowly entering 4~6cm, when urine is seen to be flowing out, it is inserted for another 2cm, and then the catheter can be completed by injecting water into the airbag. The indications for female catheterization include urinary retention, urological surgery, bladder irrigation, preoperative catheterization for obstetrics and gynecology surgery, etc. It can also be used for observation of water intake and output after rehydration in critically ill patients. If urinary catheterization is needed, it needs to be done in the hospital by professional medical personnel.