This study aims to investigate the effects of medium and long-chain triacylglycerols （MLCT） on lipid composition and lipid metabolism in rat livers in the short term. Male SD rats were randomly divided into Control group， MLCT group， MCT group and HORO group. The rats were fed with oil at the dose of 1 g/100 g body weight per day for 2 weeks. The results showed that compared with HORO group， MLCT significantly decreased the contents of triacylglycerol （TG） and total cholesterol （TC） in plasma， and also decreased low density lipoprotein-cholesterol （LDL-C）. MLCT significantly inhibited the increase of liver weight， reduce the contents of TC and TG in livers， and significantly increase the ratio of apolipoprotein A1/ apolipoprotein B. The fatty acid compositions of triacylglycerols and phospholipids in the livers of rats in each group changed greatly， suggesting that the intake of different lipids would lead to changes in the fatty acid of the liver. In MCT group， the levels of hormone-sensitive triglyceride lipase （HSL）， cyclic adenosine monophosphate （cAMP） and protein kinase A （PKA） were the highest， while the levels of adipose triacylglyceride lipase （ATGL） were the lowest. On the contrary， the levels of HSL， cAMP and PKA in HORO group were the lowest， while the levels of ATGL in HORO group were the highest. The levels of lipid metabolism related enzymes in MLCT group were between that of MCT group and HORO group， and were higher than those in Control group. This study suggested that within two weeks， MLCT could improve lipid metabolism in rats， increase the efficiency of lipid metabolism in livers， and reduce the risk of lipid metabolism and its related diseases.