Objective: To study the effect in patients with mid-low rectal cancer operation on anorectal function. Methods: 100 cases of patients with mid-low rectal cancer were selected from January 2012 to January 2015 years in our hospital, and patients with the distance from distal margin of tumor to the anal verge ≤5 cm were in low group, 5~10 cm in mid-low group, 50 cases in each. All patients were with low anterior resection, used HIDA anorectal clinical function evaluation system to evaluate anorectal function score of two groups; observed the patients’ defecation and tested the patients with anorectal function pressure tester. Results: After operation, incidence rate of daily out of control, weekly out of control, exhaust control, discharge of exhaust control, setting it out of control etc. in low group was significantly higher than those of mid-low group. Occasionally out of control and the normal rate of bowel function of mid-low group were higher than those of the low group; the defecation function of the low group was lower than that of the mid-low group, and the difference was statistically significant (P<0.05). Before operation, the difference of clinical anorectal function score between the two groups showed no statistical significance (P>0.05); 3, 6 and 12 months after operation, the anal rectal function scores in the low group was higher than that in the mid-low group, the difference was statistically significant (P<0.05). After surgery, anal maximal systolic blood pressure, anal resting pressure, anal maximal contraction time, rectoanal inhibitory reflex pressure drop of mid-low group were significantly higher in the low group, anorectal manometry ARM in low group was worse than that in mid-low group. Conclusion: Anorectal dysfunction after surgery in patients with low rectal cancer was significant than those patients in mid group. In the treatment of patients with low rectal cancer, anorectal function should be comprehensive assessed, fighting to preserve the anal function of patients.