Abstract： Objective To investigate the effects of rotating pulsed magnetic field on platelet derived growth factor a (PDGF-A) expression in periodontal tissue during tooth movement. Methods 30 white rabbits were random divided into 6 groups with 5 rabbits each group,including groups of 1,3,5,7,14 and 21 days. Under anesthesia condition by 2% pentobarbital sodium,the stainless coil springs were fixed between the first maxillary molar and the incisor producing the force of 80g. The experimental group was treated by rotating pulsed magnetic field and the force, the control group was only treated by t he force. The expression of PDGF-A was half-quantitatively investigated through immunohistochemical analysis. Results The expression of PDGF-AA in the experimental group enhanced apparently compared with that in the control group. There were significant differences among the 5,7, and 14day groups (5. 28 ± 0. 14 vs 2. 03 ±0. 18,7.63±0.27 vs 2. 84 ±0. 12,3.52 ±0. 16 vs 1.65 ±0.03;8.10±0.13 vs 4. 30 ±0. 21,13. 27 ±0. 31 vs 6.47 ± 0.15,5.66 ± 0.22 vs 3. 15 ± 0. 27, P ＜ 0. 05). The expression of PDGF-AA of 7 day group was higher than that of other groups. Conclusion Rotating pulsed magnetic field promotes the expression of PDGF-A in the periodontal tissue and alveolar bone remodeling.