This study aimed to explore the effect of Bifidobacterium animalis F1-7 on the improvement of atherosclerotic inflammation. Arteriosclerosis model ApoE-/- mice were orally administered with B. animalis F1-7 for 12 weeks. The probiotic intervention reduced the plaque areas in aorta and the accumulation of macrophages, and downregulated the expression of toll-like receptor 4 (TLR4)/nuclear factor κB (NF-κB) pathway to reduce the levels of inflammatory factors. The widely-targeted metabolomics analysis showed that acetyl-L-carnitine (ALC) in the intestine of atherosclerotic mice was significantly increased after B. animalis F1-7 intervention. Correlation analysis proved that ALC was associated with atherosclerotic inflammatory response. By using oxidized low density lipoprotein induced macrophage foam cells, we further verified that ALC could reduce lipid accumulation and inflammatory response in foam cells by downregulating the TLR4/NF-κB pathway. Finally, our results revealed that B. animalis F1-7 upregulated the metabolite ALC to downregulate the inflammatory responses, leading to the reduction of plaque accumulation of atherosclerosis.