Objective To analyze the therapeutic effect of gingivectomy combined with apically reposition flap surgery in the treatment of chronic periodontitis (CP) complicated with Ⅲ degree furcation involvement. Methods A total of 76 patients with CP and furcation involvement (Ⅲ degree) in our hospital from January 2019 to January 2021 were selected and randomly divided into group A and group B, with 38 cases in each group. Group A was treated with gingivectomy combined with apically reposition flap surgery, and group B was treated with conventional surgery. The total effective rate, periodontal index and complications of the two groups were compared. Results The total effective rate of group A was higher than that of group B (P＜0.05); the keratinized gingival width (WKG), vertical probing depth (VPD), clinical attachment level (CAL), gingival bleeding index (SBI) and plaque index (PLI) in group A were better than those in group B (P＜0.05); the incidence of complications in group A was lower than that in group B (P＜0.05). Conclusion Gingival combined with apically reposition flap surgery can improve periodontal index and reduce postoperative complications. The curative effect is ideal and worthy of application.