Abstract: Objective：Porphyromonas gingivalis could produce cyclic diguanylate (c-di-GMP) as a kind of virulence factor. This study investigated the effect of c-di-GMP on the regulation of M1 type macrophage polarization in vitro. Methods： In this study, mice derived RAW 264.7 macrophages were stimulated with different concentrations (0.25, 1, 4, 16, 64 μg/mL) c-di-GMP for different time (3, 6, 12 and 24 h). The gene and protein expression levels of IL-6, TNF-α, IL-23, IL-10 were detected by qPCR and ELISA. Flow cytometry was used to detect the expression of markers on the surface of macrophages. Results：qPCR results showed that after c-di-GMP stimulated RAW 264.7 cells, the mRNA expression of TNF-α, IL-6 and IL-23 was increased with the concentration and time of c-di-GMP in different degrees, which was dose and time dependent. The expression of IL-10 was not significantly increased in each group. ELISA results showed that the secretion of cytokines were according with the expression level of mRNA. Flow cytometry results showed that after c-di-GMP stimulated RAW 264.7 cells, the double positive rate of F4/80 and CD86, the single positive rate of CD86 and CD206 were significantly increased. Conclusions：C-di-GMP could stimulate the expression of TNF-α, IL-6 and IL-23, and induced M1 type macrophage polarization leading to the inflammatory reaction, suggesting that c-di- GMP may play an important role in the development and progression of periodontitis.