Abstract: Objective To evaluate the clinical efficacy of Milligan-Morgan hemorrhoidectomy combined with purse-string suture in the treatment of grades Ⅲ-Ⅳ mixed hemorrhoid. Methods A total of 136 patients with grade Ⅲ and Ⅳ mixed hemorrhoids admitted to our hospital between December 2015 and December 2017 were enrolled and divided into control group and observation group according to the different surgical methods, with 68 cases in each group. The control group received Milligan-Morgan hemorrhoidectomy, while the observation group received Milligan-Morgan hemorrhoidectomy combined purse-string suture. The surgical analysis related indexes (operation time, wound healing time, hospitalization time), postoperative anal pain (VAS), postoperative anal margin edema, incidence of postoperative complications (urine dysfunction, postoperative bleeding, anorectal stenosis, skin formation) and clinical outcomes were compared retrospectively. Results There was no significant difference in the operation time between the two groups (P>0.05), but the wound healing time and hospitalization time in the observation group were significantly lower than those in the control group (all P<0.05). The VAS score and the anal edema score of the anus pain were decreased in both groups within 7 days after the surgery, and these score on D1,D3, D5 and D7 after the surgery in the observation group was significantly lower than those in the control group (all P<0.05). The urinary dysfunction score and postoperative bleeding score in the observation group were significantly lower than those in the control group (all P<0.05). The incidence of anorectal stenosis and skin formation in the observation group was significantly lower than that in the control group (all P<0.05). The total effective rate was 98.53% in the observation group and 95.59% in the control group. There was no significant difference in the total effective rate between the two groups (P>0.05). Conclusion The Milligan-Morgan hemorrhoidectomy combined with purse-string suture for grades Ⅲ-Ⅳ mixed hemorrhoid can achieve a similar clinical efficacy to Milligan-Morgan hemorrhoidectomy. However, the Milligan-Morgan hemorrhoidectomy combined with purse-string suture can promote the wound healing, reduce postoperative pain and decrease the incidence of postoperative complications. It is worthy of clinical application.