Abstract: Bile acids (BAs) are a group of endogenous steroid molecules that regulate lipid, glucose and energy metabolism. They play an important role in maintaining body homeostasis and physiological functions as key signaling molecules for host and gut microbial metabolism. The accurate characterization and quantification of BAs in vivo is of great importance in basic and clinical research. Over the past decades, enzymatic assay, enzyme-linked immunoassay, nuclear magnetic resonance (NMR), chromatography, and other related techniques have been developed and applied to the detection of BAs. The diverse structures of BAs, the existence of isomers and the complex matrix of biological samples pose great challenges for the detection of endogenous BAs. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) is a robust analytical technique that combines the rapid separation capacities of UPLC with the powerful structural identification capabilities of MS/MS, facilitating the more rapid separation, characterization and accurate quantitative of target analytes in biological samples. UPLC-MS/MS has been widely used in the quantitative analysis of BAs in recent years for its high selectivity, high sensitivity, and high accuracy. This paper summarized the biosynthetic pathways of BAs, sample pretreatment methods, common analytical detection techniques, and highlights the current status of the application of UPLC-MS/MS technology in the analysis of endogenous BAs over the past five years, to provide a reference for the accurate detection of endogenous BAs and further research development and application.