Abstract: The gut microbiota and bile acids together constitute an important regulatory network within the gut-liver axis. After being synthesized in the liver, bile acids enter the intestine, where they undergo deconjugation, dehydroxylation, oxidation, and isomerization mediated by the gut microbiota, thereby forming a bile acid prof ile with diverse functional activities and biological ef fects. Conversely, bile acids infl uence the composition and function of the gut microbiota through their antimicrobial properties, receptor-mediated signaling, and regulatory ef fects on the intestinal barrier. In recent years, increasing research on the gut microbiota-bile acid axis has suggested that dysregulation of this axis not only participates in the development and progression of metabolic associated fatty liver disease, alcoholrelated liver disease, virus-related liver disease, cholestatic liver disease and hepatocellular carcinoma, but is also closely associated with infl ammatory activity, the degree of fibrosis, therapeutic response, and prognosis. Integrated analysis of bile acid prof iles and microbiota characteristics is expected to provide new insights into noninvasive stratif ication, dynamic monitoring, and precise intervention for liver diseases. This review focused on the basis of bidirectional regulation between the gut microbiota and bile acid prof iles,and axis-based diagnostic and therapeutic strategies, with the aim of providing a reference for related research and clinical translation.