Objective To study fluid flow within alveolar bone under orthodontic and occlusal loading, so as to provide references for understanding the regulatory mechanism of bone remodeling during orthodontics. Methods An animal model for orthodontic tooth movement on rats was first constructed. The finite element model of tooth-periodontal ligament-alveolar bone was established based on micro-CT images and the strain field in alveolar bone under orthodontic or constant occlusal loading was analyzed. Then finite element model of alveolar bone was constructed from the bone near the cervical margin or apical root of mesial root. The fluid flow in this model under orthodontic and cyclic occlusal loading was further predicted by using fluid-solid coupling numerical simulation. Results The fluid velocity within alveolar bone cavity mainly distributed at 0-10 μm/s, and the fluid shear stress (FSS) was mainly distributed at 0-10 Pa. FSS on the surface of alveolar bone near the apical root was higher than that close to the cervical margin. Conclusions FSS at different levels could be produced at different location within alveolar bone cavity under orthodontic and cyclic occlusal loading, which might further activate biological response of bone cells on the surface of trabeculae and finally regulate the remodeling of alveolar bone and orthodontic movement of tooth. The results provide theoretical guidance for the clinical treatment of orthodontics.