Objective: To introduce the experience of reconstructing the pelvic floor with a pedicled large omental flap combined with a basement membrane biological mesh in combined pelvic organ resection for locally advanced or locally recurrent rectal cancer combined with sacrococcygeal resection, and to discuss the feasibility, safety, and near-term therapeutic efficacy of this technique. Methods: For patients with sacrococcygeal resection of combined pelvic organs, a basement membrane mesh was used to rebuild the pelvic floor with a pedicled greater omentum flap to isolate the abdominopelvic cavity. The main operation was to pull the greater omentum, which preserved the double vascular arches, to the pelvic floor to cover the pelvic floor, and then the mesh was used to cover the posterior peritoneal defect and pelvic inlet with absorbable sutures of 2-0 or thicker. Results: In this study, a retrospective cohort study was used to collect clinical data through the China Rectal Cancer Combined Pelvic Organs Resections Case Database. Twenty patients with locally advanced or locally recurrent rectal cancer without extra-pelvic metastasis or only oligometastases underwent combined pelvic organ and sacrococcygeal resection in the Department of Anal and Intestinal Surgery of the Second Affiliated Hospital of the Naval Military Medical University during the period of July 1, 2022, to June 30, 2023, and 10 patients underwent simple basement membrane resection with a simple basement membrane. Among them, the pelvic floor were reconstructed by basement membrane mesh alone in 10 cases (mesh only group), and 10 cases were reconstructed the pelvic floor by pedicled large omental flap combined with basement membrane mesh (omental flap-combined mesh group). The recent outcomes of the two groups of patients were studied comparatively. Comparison of baseline data and intraoperative conditions between the two groups showed no statistically significant differences (all P>0.05); the drain removal time in the omental flap-combined mesh group was 26.7 (19-42) days, which was shorter than that in the mesh only group, which was 40.4 (24-56) days (U=4.125, P=0.001); The empty pelvis healing time in the omental flap-combined mesh group was 29.4 (23~43) days, which was shorter than that of 42.2 (27~58) days in the mesh-only group (U=4.043, P=0.001); the differences were all statistically significant. The postoperative complication rate of grade ≥III in the omental flap-combined mesh group was 1/10, which was lower than that of 6/10 in the mesh-only group; the difference was not statistically significant when comparing the two groups (P = 0.057). Follow-up ended on 09/30/2023, with a median follow-up of 9.5 (3-15) months in 20 patients, and all 20 cases survived during the follow-up period, with no tumor recurrence at the surgical site. Conclusion: In locally advanced or locally recurrent rectal cancer undergoing combined pelvic organ resection with sacrococcygeal, compared with reconstruction of the pelvic floor by basement membrane mesh alone, reconstruction of the pelvic floor and isolation of the abdominopelvic cavity by a pedicled greater omentum flap combined with a basement membrane mesh is safe and feasible.