To analyze the effect of self-locking bracket appliance in orthodontic treatment of patients with chronic extensive periodontitis. Methods A total of 70 patients with chronic extensive periodontitis admitted to Beijing Jiachen Ruiguan Dental Clinic from January 2020 to July 2022 were randomly divided into control group and observation group, with 35 patients in each group. The control group was treated with traditional MBT straight wire brackets, and the observation group was treated with self-ligating brackets. The clinical efficacy, periodontal index and quality of life were compared between the two groups. Results The total effective rate of treatment in the observation group was 94.29%, which was higher than 60.00% in the control group (P <0.05). After treatment, CAL, PLI, PD and SBI in the two groups were lower than those before treatment, and those in the observation group were lower than those in the control group (P <0.05). After treatment, GR in the two groups was higher than that before treatment, and that in the observation group was higher than that in the control group (P <0.05). After treatment, the scores of physical condition, condition, social condition, living condition and total score of the two groups were higher than those before treatment, and those of the observation group were higher than the control group (P <0.05). Conclusion The application of selflocking bracket appliance in orthodontic treatment of patients with chronic extensive periodontitis is effective, which can effectively improve the periodontal index and improve their quality of life.