Objective: To study the physiology value of colonic pouch anastomosis after rectal cancer excision. Methods:Forty-six patients with total mesonectal excision for carcinoma were randomized to either a straight (GroupA, n=23) or a colonic pouch anastomosis (Group B,n=23). The neorectal physiologic function of patients in both groups was evaluated, which included laboratory studies. Results: Sphincter pressures in both groups were similar. Preoperative compliance of the rectum was restored after surgery in the Group B, 0.296 (0.224-0.347) L/Kpa, but there was a significant decrease after surgery in the Group A, 0.194 (0.112-0.235) L/Kpa P＜0.001. By a multiple regression analysis, neo-rectal compliance was associated with favorable clinical function, and hypermotility of the canal was associated with adverse clinical function. Conclusion: Colonic pouch-anastomosis restores neorectal compliance, which is important for good function after iow anterior resection.