Objective:To study the effects of metformin on oxygen glucose deprivation and reoxygenation (OGD/R)-induced microglial inflammatory reaction. Methods: To establish the OGD/R model of microglia (BV-2 cells), BV-2 cells were pretreated with different concentrations (0.02, 0.20 and 2.00 mmol/L) of metformin, the effective concentration of metformin was determined by MTT and lactate dehydrogenase (LDH) assays. The supernatant of IL-1-茁 was determined by enzyme-linked immunosorbent assay, expressions of nuclear factor kappaB and CD11b were analyzed by Western blot and immunofluorescence,respectively. Results: Metformin (2.00 mmol/L) decreased the release of OGD/R-induced LDH from BV-2 cells and increased MTT activity, reduced the expression of cell surface molecule CD11b, inhibited nuclear translocation of NF-kappaB, and decreased production and release of IL-1-茁. Conclusion: Pretreatment with metformin could reduce OGD/R-induced microglia inflammatory response.