Inclusion Criteria:  Age between 18-75 years old Pathologically confirmed as rectal adenocarcinoma The tumor is located in the middle or lower rectum Preoperative MRI assessment is T2-4 N+M0 Lateral lymph node short diameter ≥ 5 mm (MRI) Signed informed consent  Exclusion Criteria:  Previous history of malignant colorectal tumors Multiple abdominal or pelvic surgeries were performed Complicated with bowel obstruction, perforation or bleeding Patients undergoing palliative surgery Patients with severe liver and kidney dysfunction, cardiopulmonary dysfunction, blood coagulation dysfunction, or combined with serious underlying diseases that cannot tolerate surgery Have a history of severe mental illness Pregnant or breastfeeding women （8) Patients previously treated with iliac artery surgery (or its branches)  (9) R0 resection cannot complete (10) ASA grade ≥ IV