Objective To establish an inflammation model by stimulating BV2 microglia by lipopolysaccharide, and to explore the regulation effect of ginsenoside Rg1 on inflammation by activating peroxisome proliferator activated receptor γ(PPARγ) receptor protein.  Methods BV2 microglia were randomly divided into control group, model group, ginsenoside Rg1 group, rosiglitazone group and GW9662 group. The control group did not do any treatment, the model group was treated with 1 mg/L lipopolysaccharide, and the other groups were treated with lipopolysaccharide added with 0.4mmol/L ginsenoside Rg1, 10 μmol/L rosiglitazone or 10 μmol/L respectively. GW9662. The proliferation of BV2 microglia in each group was detected by CCK-8 method; PPAR-γ, phospho-NF-κB p65 (p-NF-κB p65), induced expression of inducible nitric oxide synthase(iNOS) and human arginase 1(ARG-1) proteins. ELISA was used to detect the inflammatory factors interleukin-1β(IL-1β), interleukin-6(IL-6), interleukin-8(IL-8) and the content of tumor necrosis factor-α (TNF-α).   Results Compared with the control group, the cell proliferation rate in the model group was significantly increased, and the contents of IL-1β, IL-6, IL-8 and TNF-α increased significantly. The results of immunofluorescence and Western blotting showed that iNOS and p-NF-κB p65 increased significantly, and the positive expressions of PPARγ and ARG-1 decreased significantly(both P＜0.01). The expression level of TNF-α decreased, the positive expressions of iNOS and p-NF-κB p65 decreased significantly, and the positive expressions of PPARγ and ARG-1 increased significantly(all P＜0.01).   Conclusion Ginsenoside Rg1 inhibits the inflammatory response of BV2 microglia after lipopolysaccharide stimulation, and its mechanism may be related to the regulation of PPARγ/NF-κB pathway to promote the M2-type polarization of microglia.