Abstract：Objective：To observe the clinical effect of the therapy of Bazhen tang and Qingwei powder combined with metronidazole on periodontitis and its effects on Sulcus Bleeding Index(SBI)， Gingival Index(GI)， Probing Depth(PD) and Plaque Index(PLI). Methods：A total of 80 patients with periodontitis were divided into the control group and the observation group by random number table， with 40 cases in each group. The control group was treated with metronidazole， and the observation group was additionally treated with Bazhen tang and Qingwei powder. The levels of periodontal related indexes were compared between the two groups before and after treatment， and clinical effects and adverse reactions were evaluated. Results：After treatment，the total effective rate in the observation group was significantly higher than that in the control group(P＜0.05). After treatment，the levels of SBI，GI，PD and PLI in both groups were decreased when compared with those before treatment，and those in the observation group were lower than those in the control group(P＜0.05). There was no significant difference in the incidence of adverse reactions between the two groups(P＞0.05). Conclusion： The therapy of Bazhen tang and Qingwei powder combined with metronidazole has a definite therapeutic effect on the treatment of periodontitis，which can inhibit the growth of dental plaque with great safety.