Abstract: Objective: To evaluate the effect of colonic pouch anastomosis on improving defecation after low anterior resection for rectal carcinoma. Methods: From 1999 to 2003, 70 patients who underwent low anterior resection were divided into two groups: 5 cm colon J- pouch anastomosis group (CAP group, n=30), and end- to- end anastomosis group(EEA group, n=40). The rectal pressure and defecation of the patients were compared at 6, 9, 12 and 18 months after surgery. Results: Postoperative death,temporary colostomy and anastomosis leakage were not seen in either group. Anastomotic stricture was observed in one patient in the CAP group and in two patients in the EEA group. Postoperative ileus occurred in one patient in the CAP group and it recurred 9 to 18 months after surgery. The rectal pressure and defecation of the CAP group were better than those of the EEA group at 6 months after surgery, with a significant difference (P<0.05). The encopresis score of the CAP group was better than that of the EEA group at the 9th month postoperatively(P<0.05) and no significant difference was found in other indices between the two groups. Twelve months after the surgery, the above indices in both groups decreased into the normal range, without a significant difference between the two groups (P>0.05). Conclusion: For patients with low anterior resection of middle and low rectal carcinoma, J-pouch coloanal anastomosis can improve postoperative defecation within 9 months.