With the increasing maturity of laparoscopic techniques in colorectal cancer surgery, minimizing peritoneal and abdominal wall trauma, alleviating postoperative pain and surgical site complications, and seeking safer and more effective minimally invasive approaches have become important research directions in colorectal surgery. To explore the safety and feasibility of a retroperitoneal approach combined with natural orifice specimen extraction surgery (NOSES) for rectosigmoid cancer, this study reports a case of a female patient with rectosigmoid adenocarcinoma who successfully underwent D3 lymph node dissection (Japanese Colorectal Cancer Society standard, dissection to the central lymph nodes) and radical resection surgery using a combination of retroperitoneal approach and transrectal specimen extraction. The procedure was successfully completed, and the patient recovered well postoperatively. There were no perioperative complications. Preliminary results indicated that the combined retroperitoneal approach and NOSES Ⅵ technique for rectosigmoid cancer was technically feasible and theoretically held the potential to integrate the advantages of both minimally invasive techniques. However further case validation is needed.