Objective To compare the clinical effects of one-stage anastomosis on patients with middle and lower rectum carcinoma and intestinal obstruction and the ones without intestinal obstruction, and to evaluate the safety and feasibility of patients with middle and lower rectum carcinoma and intestinal obstruction undergoing one-stage anastomosis. Methods The data of patients diagnosed definitely by pathology as middle and lower rectum carcinoma underwent one-stage anastomosis in West China Hospital of Sichuan University between January 2007 and December 2008 was retrospectively analyzed. The clinical effects were compared between intestinal obstruction group and non-intestinal obstruction group. Results During this period, 525 patients were included into intestinal obstruction group (n=87) and non-intestinal obstruction group (n=438). Among the patients included, there were 307 males and 218 females. Ages were from 25 to 85 years, and the average age was 60 years old. According to tumor histology, there were 487 cases of adenocarcinoma, 29 of mucinous adenocarcinoma and 9 of other types. According to the degree of tumor differentiation, there were 140 cases of low differentiation, 372 of middle differentiation and 13 of high differentiation. According to TNM stage, there were 4 cases of stage 0, 93 of stageⅠ, 189 of stage Ⅱ, 202 of stage Ⅲ and 37 of stage Ⅳ. Constituent ratio of gender, distributions of distances from tumor to anus, TNM stages and differentiation degrees of tumor were significantly different between intestinal obstruction group and non-intestinal obstruction group (Plt;0.05); and there was no statistical difference in the age, pathological types， significant internal medical complications and operative types between the two groups (Pgt;0.05). There was no statistical diffe rence in operative duration and intraoperative blood loss between the two groups (Pgt;0.05). There was no statistical difference in postoperative time of first defecation, first out-of-bed activity and first oral feeding, and postoperative hospital stay between the two groups (Pgt;0.05); while time of first aerofluxus was earlier in intestinal obstruction group than that in non-intestinal obstruction group (Plt;0.05). There was no statistical significance in the disease incidence of postoperative complications between the two groups (Pgt;0.05). Conclusions Comparing with patients with non-intestinal obstruction, there is no significant evidence shows that one-stage anastomosis will affect the rehabilitation and increase the risk of complications in patients with middle and lower rectum carcinoma and intestinal obstruction. It is considered that it would be safe and feasible for patients with middle and lower rectum carcinoma and intestinal obstruction to have one-stage anastomosis; however, it is necessary for us to have more researches to evaluate the long-term clinical effect.