Abstract：Objective：To observe the clinical effect of Gegen Qinlian tang combined with orthodontic treatment on severe periodontitis. Methods：A total of 80 patients with severe periodontitis were randomly divided into two groups；40 patients in the control group were given orthodontic treatment， and 40 patients in the study group were given Gegen Qinlian tang combined with orthodontic treatment. The observation period was 3 months. After treatment，the two groups were observed and compared with each other in terms of plaque index，probing depth of periodontal pockets and sulcus bleeding index，and the clinical effect and adverse reactions were also evaluated. Results：The total effective rate was 95.00% in the study group and 75.00% in the control group，the difference being significant(P＜0.05). After treatment，the plaque index，the depth of periodontal pockets and the sulcus bleeding index in the study group were lower than those in the control group， the difference being significant(P＜0.05). During the treatment， no adverse reactions occurred in the study group， and the incidence rate of adverse reactions in the control group was 5.0% (1 case each with nausea， vomiting and poor appetite)， there being no significant difference(P＞0.05). Conclusion： The therapy of Gegen Qinlian tang combined with orthodontic treatment has a positive effect on severe periodontitis， and can significantly improve the plaque index， the depth of periodontal pockets，and the sulcus bleeding index.