In order to explore the active constituents of total triterpenoids from Inonotus hispidus and their ability to reduce lipid in vitro, ultrahigh liquid phase tandem high resolution mass spectrometry (UPLC-TOF-MS/MS) was used to qualitatively analyze the total triterpenoids, and the HepG2 cell high lipid model was established by induction of oleic acid. The survival rate and lipid content of the established HepG2 cell model were taken as indicators to investigate the lipid-lowering ability of total triterpenoids purified from Inonotus hispidus in vitro.The results showed that a total of 8 triterpenes were identified by UPLC-TOF-MS/MS based on the elution sequence, retention time, molecular weight, mass spectrometry and information referred to literature. Experiments in vitro showed that HepG2 cells incubated with 400 μmol/L oleic acid for 24 h had the highest lipid accumulation amount. Compared with other concentration groups, the decrease in lipid content was most significant when the total triterpenoids was 250 μg/mL, the total cholesterol, triglycerides and low density lipoprotein cholesterol contents decreased 41.86%, 44.44%, 44.02%, respectively, while the high density lipoprotein cholesterol content increased 57.33% in contrast to the control group.Our finding confirms the lipid-lowering function of triterpenes from Inonotus hispidus in vitro, and provides experimental basis for the development of new lipid-lowering functional foods.