In order to explore the chemical constituents of Foeniculum vulgare Mill.cortex in the treatment of liver fibrosis,and to reveal its pharmacodynamic material basis and mechanism of action.In this study,UPLC-Orbitrap-MS/MS technology was used to qualitatively identify the chemical constituents of the ethanol extract,petroleum ether fraction,ethyl acetate fraction,n-butanol fraction and water fraction of the F. vulgare cortex.According to the mass spectrometry fragmentation rule,reference substance verification and literature search,58 common compounds of each component were speculated and identified.MTT assay was used to detect the effect of each component on the proliferation of HSC-T6 cells,and the potential active compounds against liver fibrosis were screened by spectrum-effect relationship.The results of spectrum-effect relationship showed that dihydrocapsaicin,harmine and isoscopoletin contributed more to the anti-hepatic fibrosis of F. vulgare cortex.The anti-hepatic fibrosis activity and mechanism of monomeric compounds were verified in vitro.The results showed that dihydrocapsaicin,harmine and isoscopoletin had a good inhibitory effect on activated HSC-T6 (P<0.01,0.001),and could inhibit the expression of α-SMA (P<0.01,0.001).Dihydrocapsaicin and harmine had strong pro-apoptotic effects and could down-regulate the relative expression of Bax/Bcl-2 and Caspase3 (P<0.05,0.01).It is indicated that the pharmacodynamic substances of F. vulgare cortex against liver fibrosis may be dihydrocapsaicin,harmine,isoscopoletin,scopoletin,7-hydroxycoumarin,etc.The mechanism may be to inhibit the activation of hepatic stellate cells and regulate the expression of Bax/Bcl-2,which reflects the multi-component and multi-target anti-liver fibrosis characteristics of F. vulgare cortex.