【Abstract】Objective To explore the application of anal pressure measurement device in evaluating the anal function in patients with rectal cancer before and after anal sphincterpreservation surgery. Methods Anal pressure measurement was performed in 63 patients with rectal cancer who underwent anal sphincterpreservation surgery in the department of anorectal surgery, and 35 normal people were selected as the control group at the same time. The anal dynamic indexes in the control group before surgery and those in patients with rectal cancer at 1 month, 6 months and 12 months after surgery were detected. Results There were no significant differences in ARP, MSP, RRP, UV, RVST, MTV, RC, HPZ and RAIR between the normal control group and patients with rectal cancer before surgery (P＞0.05). One month and 6 months after surgery, the excellent and good rate of defecation function (22.22%, 31.75%) were significantly lower than that before operation (9048%) (χ2=59.660, 45.718, P＜0.05). 12 months after surgery, there were no significant differences (χ2=3037, P＞ 0.05). One month, 6 months and 12 months after surgery, MTV and RAIR were significantly lower than those before surgery (P＜0.05) while MSP showed no significant difference (P＞0.05). Conclusion〓Low resection for rectal cancer has effect on anal function in patients in short term, and the anorectal dynamic indexes can be used to evaluate the recovery of anal function after surgery.