Abstract: Objective: To explore the relationship between Osterix (Osx) and the remodeling of periodontal tissue via observing the expression of Osx in rats periodontal ligaments during the orthodontic tooth movement．Methods: 54 male SD rats were randomly divided into 9 groups, according to tooth movement time points of 0,3,6,12,24 h and 3,5,7,14 d. The orthodontic appliance was placed between the upper left first molar and the upper incisors of each rat, while the upper right first molar as the control group. Osx expression in the tissue of each rat was determined by the immunohistochemical SABC method. Results: In the control group, Osx expressed at a low level in the rat periodontal ligament.While in the experimental group, Osx expression reached the maximum after 5 d, furthermore, the Osx immunoreactivity was higher at the tension side than that at the compression side．Conclusions: Osx played an important role in alveolar bone remodeling during the orthodontic tooth movement．