Lipopolysaccharide (LPS) stimulates macrophages to release proinflammatory cytokines. MicroRNAs (miRNAs) are short noncoding RNAs that are involved in inflammatory reaction. Our previously study identified the downregulated expression of mmu-miR-27a-5p in RAW267.4 cells treated with LPS. To dissect the mechanism that mmu-miR-27a-5p regulates target genes and affects proinflammatory cytokine secretion more clearly, based on previous bioinformatics prediction data, one of the potential target genes, MCPIP1 was observed to be upregulated with qRT-PCR and western blot. Luciferase reporter assays were performed to further confirm in silico prediction and determine that MCPIP1 is the target of mmu-miR-27-5p. The results suggested that mmu-miR-27a-5p directly targeted the 3'-UTR of MCPIP1 and the interaction between mmu-miR-27-5p and the 3'-UTR of MCPIP1 is sequence-specific. MCPIP1 overexpression decreased the secretion of IL-6, IL-1β, and IL-10 in macrophage cells stimulated with LPS. Our findings may provide the important information for the precise roles of mmu-miR-27a-5p in the macrophage inflammatory response to LPS stimulation in the future.