To investigate the effects of interaction between body mass index and diabetes on postoperative recurrence of perianal abscess. Methods:A total of 790 inpatients with perianal abscess from January 2015 to March 2016 in the First Affiliated Hospital of Guizhou University of Traditional Chinese Medicine were retrospectively analyzed. The interaction between BMI and diabetes on postoperative recurrence was analyzed by Cox proportional hazard model and likelihood ratio test. Results:In anorectal abscess patients with diabetes,each additional 1Kg/m2 of BMI would increase the risk of postoperative abscess recurrence by 28% (HR=1.28,95% CI 1.05,1.56,P for interaction＝0.03). Conclusion:The risk of recurrence of abscess after operation is higher in people with diabetes mellitus and in people with higher BMI,which is helpful for early identification of high risk patients and improvement of prognosis.