Objective To detect the role of miR-34a on macrophage inflammation and polarization under high glucose conditions.Methods Mouse macrophages were collected and cultured during high glucose for 3－28 days.RT-qPCR was used to detect the expression of miR-34a,iNOS,MCP-1 and Arg-1 mRNA.Then miR-34a was over-expressed or silenced,ELISA was used to detect the expression of IL-6,IL-1β,TNF-α and qRT-PCR was used to detect the expression of iNOS and MCP-1 mRNA.Western blot was used to detect the expres-sion of Notch1.Results Expression of miR-34a increased under high glucose conditions in RAW264.7 cells continuously.Over-expression of miR-34a promoted the expression of MCP-1 and iNOS observed by RT-qPCR and increased the expression of IL-6,IL-1β and TNF-α detected by ELISA.Further studies showed that siRNA-Notch1 down-regulated the expression of miR-34a,MCP-1,iNOS,IL-6,IL-1β and TNF-α.Conclusions Chronic high glucose condition stimulates the expression of miR-34a which promotes M1 macrophage polarization and releasing of pro-inflammatory factors.