In obstetrics, with the mature use of intraperitoneal subepithelial cesarean section, cesarean sections have become more diversified and the indications for surgery have been relaxed. In our department, we have gradually developed the extraperitoneal subperitoneal cesarean section that preserves the integrity of the abdominal cavity, which is particularly suitable for pregnant women with intrauterine infections or potential infections. Indications for surgery: 1. Premature rupture of fetal membranes with potential for intrauterine infection; 2. Well-formed lower uterine segment, with the head of the fetus at term articulated and the uterine opening 2-3 cm wide is most appropriate; 3. Amniotic fluid contamination. Contraindications: 1. Abdominal surgery that requires exploration of the abdominal cavity, such as pregnancy combined with uterine fibroids, malformed uterine pregnancy, uterine rupture or rupture of the uterus, the need for emergency cesarean section; 2. placenta praevia, placenta attached to the anterior wall of the lower uterine segment; 3. fetal intrauterine distress or need to quickly deliver the fetus; 4 megacolonial; 5. the head of the fetus embedded in the too deep. Preoperative preparation and anesthesia are the same as intraperitoneal lower uterine segment cesarean section. Technical points of surgical operation: Separate the bladder from the peritoneum outside the peritoneum. According to the different ways of separating the peritoneum from the bladder, it is divided into bladder lateral entry, bladder parietal entry, hydraulic type and bladder parietal combined type. Currently, we use the combined parietal approach, which has better exposure of the operative field and facilitates operation to reduce injury. It absorbs the advantages of the parietal and lateral approach, and makes the surgical steps simplified and safe. Surgical features: The bladder fascia is incised in an arc from the left side, and the bladder is bluntly freed from the bladder apex on the left side, and the bladder is pushed from the upper left to the lower right, exposing the lower part of the uterus. Surgical steps: 1. incision of the abdominal wall: the operation is the same as the intraperitoneal lower uterine segment cesarean section, and still take the suprapubic transverse incision of the abdominal wall; 2. separation of the anterior bladder fascia; 3. freeing the bladder from the cervical hiatus; 4. separation of the bladder and uterus back to folding the peritoneum; 5. exposure of the lower uterine segment; 6. incision of the uterus, removal of the fetus; 7. clearing of the peritoneal hiatus, and checking that there is no bleeding, the interrupted sutures to close the anterior bladder fascia, and repositioning of the bladder; 8. sutures Uterine incision, the same as intraperitoneal lower uterine cesarean section; 9. Suture the abdominal wall tissue in layers. Precautions: 1. The separation of the anterior bladder fascia must be done layer by layer, and each time it is separated, it must be pulled away to the sides to reach the lateral side of the bladder, and the muscular layer of the bladder is clearly exposed.2. Before separating the bladder from the reflexed peritoneum, the anterior cervical fascia underneath it must be free from the lower uterine segment.3. The separation of connective tissues on the lateral side of the bladder must be done in layers and immediately adjacent to the bladder lateral wall and pulled away to the side, and the area of the bladder’s junction with the reflexed peritoneum is exposed Clearly. Extraperitoneal subperitoneal uterine cesarean section that preserves the integrity of the abdominal cavity has been carried out in our ward, and through our many years of clinical practice and accumulation of clinical data, we have found that this procedure does not enter the abdominal cavity, which in turn protects the integrity of the abdominal microenvironment, and the operation is safer with less collateral damage, no intervention in gastrointestinal function, and more secure surgery. However, it is important to strictly grasp the indications and contraindications, and skillfully master the technique of extraperitoneal lower uterine segment cesarean section. Advantages: 1. Because the fetus does not pass through the abdominal cavity during the operation, amniotic fluid and fetal products do not contaminate the abdominal cavity, the patient has no postoperative complications such as abdominal distension and abdominal pain, and also avoids long-term complications such as intestinal adhesions, pelvic adhesions, and chronic pelvic pain in the postoperative period. 2. Extra-peritoneal operation protects the integrity of the abdominal cavity, and the micro-environment of the abdominal cavity is not interfered with, so that the patient’s postoperative pain is light, reaction is small, the intestinal function recovers fast, feeding is early, and the hospitalization Short time, accelerated bed turnover, etc., preferred by doctors and patients.