Abstract: OBJECTIVE To analyze the effect of Eucommiae Cortex alcohol extract on periodontal disease osteoclast activating factor (IL-1β) through NF-kB signaling pathway to improve the periodontal disease of orthodontic tooth in rats. METHODS Sixty Wistar male rats of SPF grade were randomly divided into four groups:the normal group, the model group, the low and high doses of Eucommiae Cortex group, 15 rats in each group. Except the normal group, other rat model of periodontal disease was prepared. After one week of modeling, the low and high dose groups of Eucommiae Cortex were injected into the bottom of the first and second molars of the right maxillary and the buccal side of the rat with dose of 0.2 mL 0.1, 1.0 mg·mL^-1 Eucommiae Cortex. Normal group and model group were injected with equal dose of normal saline for 5 d. The expression of osteoclast activating factor (IL-1β) protein and mRNA in rat periodontal ligament fibroblasts was detected by Western-blot and real-time PCR. RESULTS Compared with the normal group, the relative expression of IL-1β and NF-kB mRNA in the fibroblasts of the model group significantly increased(P<0.05). Compared with the model group, the relative expression of IL-1β and NF-kB mRNA in the fibroblasts of low and the high dose of Eucommiae Cortex group decreased(P<0.05). Compared with the normal group, the serum IL-6 and IL-1β in the model group were significantly increased(P<0.05). Compared with the model group, the serum levels of IL-6, IL-1β and TNF-α in the low and the high dose group of Eucommiae Cortex(P<0.05). Compared with the normal group, the expression of NF-kB and IL-1β protein in the maxillary tissue of the model group significantly increased(P<0.05); compared with the model group, the expression of NF-kB and IL-1β protein in the maxillary tissue of the rats in the high and low dose of Eucommiae Cortex group was decreased(P<0.05). CONCLUSION Eucommiae Cortex alcohol extraction has a role in the periodontal disease osteoclast activating factor (IL-1β) through NF-kB signal pathway, which reduces the content of inflammatory factors in periodontal tissues and has a therapeutic effect on periodontal disease.