Objective To observe the effect of ultrasound-guided bilateral transverse abdominal muscle block (TAP) combined with PCIA with different concentrations of sufentanil on postoperative analgesia and the prolactin level after cesarean section, and evaluate its role in enhanced recovery after surgery (ERAS). Methods Ninety-six puerperae scheduled for cesarean section from May 2020 to December 2021 were randomly divided into 3 groups using a random number table. The three groups all received TAP under the guidance of ultrasound, and a patient-controlled intravenous analgesia (PCIA) with 0.5 ug/ml (S1 group, n=32), 0.75 ug/ml (S2 group, n=32), 1ug/ml (S3 group, n=32) sufentanil was used after surgery. The visual analogue scale (VAS) score of incision pain in resting state and exercise state and VAS score of contractions pain were recorded respectively at 4, 8, 24, and 48 h after operation. The serum level of prolactin at 10 minutes before surgery, 24, 48 h postoperatively were detected, respectively. The leaving bed time, the intestinal exhaust time, the first urination time, and the adverse reaction occurred after the surgery were all recorded. Results The VAS scores of incision pain at rest of group S2 and group S3 were lower than group S1 at 8,24 h after surgery (P<0.05). The VAS scores of incision pain at motion and contractions pain of group S2 and group S3 were lower than those of group S1 at 8, 24, 48 h after surgery (P<0.05). Compared with group S1, the serum level of prolactin in group S2 and S3 were higher at 24 and 48 h, postoperatively. Compared with group S3, the intestinal exhaust time (39.49±6.01) h and the incidence of nausea and vomiting (26.7%) after surgery in group S1 and S2 were lower (P<0.05). Conclusion Ultrasound-guided TAP combined with 0.75 ug/ml sufentanil for PCIA after cesarean section has good analgesic effect, little effect on the secretion of prolactin, but it can promote the recovery of gastrointestinal tract and reduce the incidence of adverse reaction, which is a positive way to promote the application of ERAS in perioperative period of cesarean section