Obesity is a prevalent chronic metabolic disorder. Artemisia capillaris Thunb., a natural plant known for its hepatoprotective and choleretic properties, is commonly brewed into Artemisia capillaris Thunb. tea (ACTE). Artemisia capillaris Thunb. rich in a variety of bioactive constituents, including organic acids, coumarins, and essential oils, which contribute to its therapeutic potential in liver health. This study evaluates the potential therapeutic effects of ACTE in a high-fat diet (HFD)-induced obese murine model by observing mouse phenotypes, conducting biochemical analyses, performing 16S rRNA gene sequencing, utilizing bile acid-targeted metabolomics, and applying molecular biology techniques to comprehensively explore the mechanisms of ACTE. The results demonstrate that ACTE ameliorates obesity and hepatic lipid accumulation in obese mice, modulates gut microbiota composition, activates the FXR signaling pathway, enhances bile acid enterohepatic circulation, strengthens intestinal barrier integrity, and alleviates liver inflammation and pyroptosis by inhibiting the NF-κB and NLRP3 signaling pathways. These findings suggest that ACTE ameliorates HFD-induced obesity in mice by modulating the gut–liver axis through interactions between the gut microbiota and its metabolites, providing a new way of eating to improve human health.