Objective To evaluate anal function in patients with rectal carcinoma after low anastomosis operation. Methods Five hundred and forty-one patients with low rectal carcinoma were followed up for 1-3 years to assess anal function after low or ultra-low Dixon anastomosis. The evaluation was based on Xu Zhong-fa Assessment Criteria of Anal Function, anastomotic position and time-to-operation. Defecation function training and rehabilitation instructions were administered after the operation. Results The evaluation of defecation function showed that in the low Dixon operation group, 75.8%(211/278) scored “excellent”, 11.8%(33/278) scored “good”, 10.1%(28/278) scored “fair” and 2.2%(6/278) scored “poor”. In the ultra-low Dixon operation group, 70.7%(186/263) scored “excellent”, 13.3%(35/263) scored “good”, 10.6% (28/263) scored “fair”, and 5.3%(14/263) scored “poor”. No statistical difference was found between the low and ultra-low Dixon groups in this evaluation (Z= –1.429,P=0.136). However, there was statistical difference in the “awareness of defecation”(Z= –4.610,P=0.000) and “sense of defecation” (Z= –5.252, P=0.000) domains between the two groups. The defecation functions were similar between the low and the ultra-low Dixon operation groups after 6-month post-operation training(Z= –0.550, P=0.582). Conclusions There is no difference in defecation function between low and ultra-low Dixon anastomotic operation patients with rectal carcinoma by nursing.