Patients with low and middle rectal cancer are most concerned about whether they can cure the tumor while preserving the original anal function and not having a permanent enterostomy. In fact, as far as the current technology is concerned, there is no technical problem in preserving anus not only for middle and high rectal cancer but also for low rectal cancer, especially the newly developed 3D laparoscopic surgery with intersphincteric sphincter or the drag-out resection anastomosis that we first reported in the international arena can perform ultra-low level anus preservation. And it can be achieved that even for such a large operation, there can be no incision or only a small incision of about 5cm in the abdomen, and the patient can go down to the floor the next day after the operation, which is completely minimally invasive. However, whether rectal cancer is ultimately anus-preserving or not depends on the oncology of whether it should be preserved, including the distance between the lower edge of the tumor and the dentate line of the upper edge of the internal anal opening, the size of the tumor, the depth of tumor invasion and whether there are lymph node metastases, as well as whether the patient already has partial fecal incontinence before surgery. In principle, it is necessary to save the life and have better postoperative stool control at the same time. If the tumor is early, the volume is small and the invasion depth is shallow, even if the location is low, it is possible to achieve radical tumor treatment and preserve the anus; on the contrary, if the tumor is large and the invasion is deep, not only is it not suitable for anus preservation, but also it may be necessary to do radiotherapy first and then surgery. Therefore, whether it is suitable for anal preservation or not depends on the specific situation of the tumor.