Abstract: Objective: To study the relevant factors for anus reservation in radical resection of ultra-low-rectal carcinoma through Logistic regression analysis, and to discuss the indications and surgical procedures. Methods: Thirty-six patients with rectal tumors within 5 cm above the anal verge were treated by surgical procedures from Apr. 2007 to Mar. 2008 in our department. The gender,age, location and size of the tumor,degree of differentiation,Dukes stage,operation methods,preoperative neoadjuvant therapy,and whether or not retainning the anus before operation were studied through Logistic regression analysis. Results: The results indicated that the above four factors were the major relevant factors for anus reservation in radical resection of ultra-low-rectal carcinoma(P=0.048-P=0.011). Conclusions: The clinical staging of the patients should be precisely assessed before operation. Patients with the tumors located within 4-5 cm above the anal verge or before Dukes stage C should receive laparoscopic radical operation; and patients with the tumors located below 4 cm above the anal verge should select multi-mode therapies,to achieve radical cure and anal reservation.