Aim To explore the anti-inflammatory mechanisms of high density lipoprotein (HDL) by observing the effects of apolipoprotein A1 (ApoA1),a major protein component of HDL,on the mouse bone barrow macrophage polarity. Methods Apo A1 (5,10,15 mg/L) were added to the cultured mice marrow-derived macrophages for 24 h.The expression of membrane molecules CD16/32,CD206 were detected using fluorescence activated cell sorting (FACS) Enzyme-linked immunosorbent assay (ELISA) were used to detect the secretion of interleukin-10 (IL-10) and IL-12 Real-time quantitative polymerase chain reaction were used to detect the expression of Toll like receptor 4 (TLR4),myeloid differentiation factor 88 (MyD88),interferon regulatory factor 5 (IRF5) mRNA. Results After incubation mice marrow-derived macrophage with ApoA1 (5,10,15 mg/L) for 24 h,the expression of CD16/32,IL-12 was decreased,expression of CD206,IL-10 expression was elevated,and the expression of TLR4,MyD88,IRF5 mRNA was decreased.Conclusion ApoA1 promote macrophages towards an anti-inflammatory M2 phenotype,which may be responsible for the anti-inflammatory effects of HDL.