Abstract: Objective　To investigate the expression characteristics of serum bile acid profiles in patients with simple obesity，further to understand the effect of bile acids inducing signaling on human body energy metabolism, and to provide experimental evidence and clues on searching potential biotherapy target. Methods　Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) assay was used to test serum bile acid profiles of 10 healthy subjects，10 subjects with overweight and 10 patients with simple obesity.  Results　A total of 14 bile acid subgroups were detected in all sera from healthy, overweight and simple obesity groups, and lithocholic acid (LCA)，taurocholic acid (TCA)，taurolithocholic acid (TLCA) and tauroursodeoxycholic acid (TUDCA) had lowest expression in all groups. The expressions of all different 14 bile acid subgroups had no statistical significance（P＞0.05）. The levels of glycochenodeoxycholic acid (GCDCA) and taurochenodeoxycholic acid (TCDCA) increased markedly in serum bile acid (FBA) profiles of simple obesity group. Both free bile acids (CBA) and conjugated bile acids from overweight and simple obesity groups were lower than those from healthy group（P＞0.05）. Conclusions　The levels of GCDCA and TCDCA increase markedly in serum bile acid profiles of patients with simple obesity，but the expressions of all different 14 bile acid subgroups have no significant difference with those of healthy subjects.

Key words: Bile acid profile, Simple obesity, Ultra-performance liquid chromatography-tandem mass spectrometry