Abstract： Objective To observe the dynamic expression and location of TGF-β1 and TGF-β receptor Ⅰ ,Ⅱ at different time in an experimental model of rat molars reversible pulpitis, to evaluate the role of TGF-β1 and TGFβ receptor Ⅰ , Ⅱ on pulp injury and repair. Methods The reversible pulpitis animal model was established by drilling the enamel without water cooling and then acid etching dentine. The maxillary and teeth of each animal were made 5μm thick serial slides. The slides were stained with hematoxylin-eosin and SABC immunehistochemical technique and then studied under the light microscope and under image analysis, all the data were statistically analyzed by analysis of variance (ANOVA) and t-test. Results Positive staining of TGF-β1 and TβR Ⅰ ,TβR Ⅱ was found in odontoblasts, pulp fibroblasts and vascular endothelial cells. In pulpitis stage,the expressions of TGF-β1 and TGF-β receptor Ⅰ , Ⅱ were increased markedly, and showed dynamic changes at different time;TGF-β1 show a peak at 5d and followed by decreased significantly. TGF-β receptor Ⅰ ,Ⅱshowed the highest at 3d ,and then decreased slightly. From 0d to 3 d,TGF-β1 and TGF-β receptorⅠ,Ⅱ showed uptrends, but their uptrends had no direct proportion relationship. Conclusion The results presented here suggested that TGF-β1 and TGF-β receptorⅠ,Ⅱ might play an important role in pulp wound and repair. The inflammatory reaction in response to TGF-β1 was mediated by TGF-β receptorⅠ, Ⅱ; Although TGF-β1 showed a possible function for the TGF-β receptor,but a direct proportion relationship couldn't be concluded.