Posterior vault puncture is a procedure commonly used in gynecology for examination, in which a doctor punctures the posterior vault of a woman with a special puncture needle and withdraws fluid for examination, mainly for further examination and diagnosis when fluid accumulates in the abdominopelvic cavity, or when intra-abdominal bleeding is suspected, and also for egg retrieval. During the operation of posterior fornixocentesis, the patient should lie flat on the surgical bed with both legs fixed by braces, fully expose the perineal area and perform routine disinfection, the detector exposes the cervix through the speculum and uses a cervical forceps to clamp the posterior lip of the cervix and pull it upward to expose the posterior fornix, disinfect the puncture site, and finally the puncture needle aspirates the diseased side and withdraws the needle. The use of posterior fornix puncture is usually done only when there is a high clinical demand, although there are certain risks and pain, but the pain is mostly mild, and the puncture needle used is also fine, even if there are side injuries are often mild. Before the examination, it should be noted that it should be performed 3-7 days after menstruation. Patients should not have intercourse 3 days before the examination, fast after 8 pm on the first day, empty the bladder before the examination, and relax during the examination. After the examination, attention should be paid to maintaining the hygiene of the perineum. It is recommended to wash the perineum with warm water daily, in addition to prohibit tub bathing for 1 week after the operation, and also avoid sexual life.