Objective：To investigate the expression levels of miR-199a-5p in the liver under various nutritional conditions and its effects on hepatic triacylglyceride（TAG）content，as well as the underlying mechanisms. Methods：RT -qPCR was used to detect the expression levels of miR-199a-5p in liver tissues of high fat diet mice. Hepa1-6 and AML12 cells were transfected with miR-199a-5p mimics，inhibitors，negative controls and pcDH-CD36-flag plasmid，respectively. The changes in biomarker expression related to lipid metabolism were detected by RT-qPCR and Western blot，and TAG content was detected by kit. The target gene of miR-199a-5p was predicted by microRNA Target Prediction Database（miRDB）and verified by the dual luciferase reporting assay. Results：The expression levels of miR - 199a - 5p in the liver of C57BL/6J mice were elevated under high - fat diet and fasting conditions. Overexpression of miR - 199a -5p reduced TAG levels in hepatocytes，while inhibition of miR - 199a -5p increased intracellular TAG content. miR-199a-5p decreased the protein expression of the fatty acid translocase CD36 by interacting with its 3′ untranslated region （3′ UTR）. Conclusion：The expression level of miR -199a -5p increases during hepatic lipid accumulation，and miR -199a -5p may reduce TAG content in hepatocytes by targeting CD36.