Abstract： Objective： To discuss the effect of baicalin on periodontitis and study its related molecular mechanism. Methods：A total of 50 specific pathogen free- grade female rats were divided into the blank group without any treatment， the Control Group One(injection of normal saline into the bottom of median gingival sulcus of maxillary second molar on the right side of buccal surface)， the Control Group Two(injection of normal saline containing lipopolysaccharide(LPS) into the same location as that of the Control Group One)，the Experiment Group One(injection of normal saline containing LPS and 0.1 μg/mL baicalin into the same location as that of the Control Group One)，and the Experiment Group 2(injection of normal saline containing LPS and 1.0 μg/mL baicalin into the same location as that of the Control Group One)，10 rats in each group. On the 9th day of experiment， a part of rats were sacrificed， and their maxillary bone was taken out； alveolar bone resorption was examined by Micro-CT. On the 9th day of experiment，venous blood was taken from the rest part of rats to culture macrophage；the expression of mRNA of transforming growth factor-β(TGF-β) was detected by reverse transcriptase polymerase chain reaction(RT-PCR)；the protein expression of TGF-β and Interleukin-1β(IL-1β)，Caspase-1，high mobility group box 1(HMGB1) was detected by Western blot. Results： There were no significant differences being found in the comparison of each detection index between the Control Group One and the blank group(P＞0.05). Compared with those in the Control Group One，in the Control Group Two，bone volume，the ratio of bone surface to bone volume，the thickness and number of bone trabecula， and the expression of protein and mRNA of macrophage like TGF- β1， as well as the expression of IL-1β，caspase-1，and HMGB1 marked by macrophage were decreased(P＜0.05)；pattern factor and spacing of bone trabecula were increased(P＜0.05). Compared with those in the Control Group Two，in the Experiment Group One and Group Two，bone volume，the ratio of bone surface to bone volume，the thickness and number of bone trabecula，and the expression of protein and mRNA of macrophage like TGF- β1， as well as the expression of IL- 1β， Caspase- 1， and HMGB1 were increased(P＜0.05)； pattern factor and spacing of bone trabecula were decreased(P＜0.05). Compared with those in the Experiment Group One，in the Experiment Group 2，bone volume，the ratio of bone surface to bone volume， the thickness and number of bone trabecula，and the expression of protein and mRNA of macrophage like TGF-β1，as well as the expression of IL-1β，Caspase-1，and HMGB1 were increased(P＜0.05)；pattern factor and spacing of bone trabecula were decreased(P＜0.05). Conclusion： Baicalin can promote secretion of TGF- β by macrophage and reduction of induced osteoclastogenesis， as well as activate the Caspase- 1/IL- 1β pathway， thus reducing alveolar bone destruction and resorption，as well as relieving periodontitis.