Objective:To observe the clinical effect of catheter drainage combined with loose thread-drawing on high anal fistula  Methods:68 cases of high anal fistula patients were randomly divided into treatment group and control group, 34 cases in each group. Patients in treatment group were treated with catheter drainage combined with loose thread-drawing; patients in control group were treated with inferior incision combined with tight thread-drawing. The curative rate, wound healing time, recurrence rate, postoperative pain, anorectal pressure changes to evaluate anal function were compared between the two groups  Results:The cure rate of treatment group and control group were 94.12% and 82.35% respectively, the treatment group was higher than control group (P<0.05); in wound healing time, the treatment group was shorter than the control group (P<0.05); in postoperative pain after surgery 7 days and 10 days, the treatment group pain score was less than the control group (P<0.05)  Conclusion:Catheter drainage combined with loose thread-drawing on high anal fistula can be increased on the cure rate and reduce postoperative pain on the basis of the effective protection of anal function.