Objective：This study aims to investigate the effect of IgG on activating signaling pathway of macrophages induced by CpG DNA. Methods：Bone - marrow derived macrophages were cultured in vitro and their surface markers and phagocytic functions were identified by flow cytometry and immunofluorescence technique. After the treatment of macrophages with IgG，CpG DNA and IgG plus CpG DNA，the activated molecules on the surface of macrophages were detected by flow cytometry，and the protein phosphorylation was detected by immuno-protein Western blot. Results：The expression rate of CD11b and F4/80 on the surface of macrophage in vitro was about 99.7 %，and the proportion of macrophage to FITC - IgG was about 70 %；IgG up-regulated the expression of CD40，CD80 and CD86 on the surface of macrophage induced by CpG DNA（P < 0.05）；IgG promotes the phosphorylation of JNK and p38 in macrophages induced by CpG DNA，but it has no effect on the phosphorylation of ERK and NF-κB；CpG DNA induces macrophages to secrete TNF-α，and combination of IgG with CpG DNA enhanced this process. Conclusion：CpG DNA activates macrophages and increases the phosphorylation of JNK and p38，and the combined treatment of CpG DNA and IgG highly induced this process；CpG DNA increased the co-stimulation molecule of CD40，CD80and CD86 on the surface of macrophages，while the co-therapy of IgG and CpG DNA highly up-regulates this expression.