Objective:To observe the effects of Zhibo Dihuang Pill combined with basic periodontal therapy on receptor activator of nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG) levels in gingival crevicular fluid of patients with periodontitis. Methods60 patients with periodontitis were randomly divided into the treatment group and control group, 30 cases in each group. The control group was treated with basic periodontal therapy, and the treatment group was treated with Zhibo Dihuang Pill based on the treatment for the control group, with a course of 4 weeks. The changes of probing depth (PD), clinical attachment loss (CAL), plaque index (PI), bleeding on probing (BOP), RANKL and OPG levels in gingival crevicular fluid and the ratio of RANKL to OPG were compared.  Results:①Compared with treatment before, the levels of PD, CAL, PI and BOP were decreased in both groups after treatment (P<0.05). After treatment, the D-value of PD and CAL between treatment before and after in the treatment group were greater than those in the control group (P<0.05). ②Compared with treatment before, the RANKL/OPG was decreased in both groups after treatment (P<0.05). In both groups, there were no statistically significant differences on the levels of RANKL and OPG between treatment before and after (P>0.05). After treatment, the D-value of RANKL and RANKL/OPG between treatment before and after in the treatment group were higher than those in the control group (P<0.05).  Conclusion:Compared with basic periodontal therapy alone, Zhibo Dihuang Pill combined with basic periodontal therapy in treating periodontitis shows the better effects on improving periodontium recovery and protecting alveolar bone. Its mechanism may be related to inhibiting the differentiation, activation and proliferation of osteoclasts.