Rectal mesentery refers to the vascular lymphatic adipose tissue on both sides and dorsal side of the rectum wrapped by the pelvic fascia (i.e., intrinsic rectal sheath), which contains only the intrinsic rectal sheath and less lymphatic adipose tissue in the area below 5-6 cm from the anus. Rectal mesentery is the main site of local spread of rectal cancer, and total resection of rectal mesentery reduces the rate of local recurrence after surgery. The inferior mesenteric arteries and surrounding lymph nodes travel to the base of the sigmoid mesentery, which is the lymph node metastasis route for the spread of rectal cancer. During surgery, rectal cancer masses need to be resected as a whole, and divided resection increases the possibility of tumor cells dispersal and increases the risk of local recurrence after surgery, and intraoperative NS irrigation is very important.