Objective: To identify chemical components in Ligustri Lucidi Fructus by simulation of its steamed products with four secoiridoid glycosides

and discuss transformation mechanism of secoiridoid glycosides in Ligustri Lucidi Fructus during steaming process. Method: HPLC was employed with mobile phase of acetonitrile-0.1%formic acid solution for gradient elution and detection wavelength at 240 nm.Agilent 6230 LC-TOF/MS coupling system was adopted.Chemical components in Ligustri Lucidi Fructus by simulation of its steamed products with four secoiridoid glycosides were determined by reference positioning

mass spectrometry data and literature reference. Result: Olivanic acid was determined in four simulation of steamed products;salidroside and two kinds of specnuezhenide isomers were detected in specnuezhenide simulation of steamed products;3

4-dihydroxy-ethyl-β-D-glucoside was identified in neonuezhenide simulation of steamed products;oleuropein and ligustroside simulation of steamed products were detected their respective glycosides of hydroxytyrosol and tyrosol. Conclusion: Property of secoiridoid glycosides in Ligustri Lucidi Fructus is instable

water and heating can make them hydrolysis to produce its secondary glycosides or glycosides

specnuezhenide can convert into its isomer during simulation process.The enhancement of tonifying liver and kidney efficacy of Ligustri Lucidi Fructus is closely related to hydrolysis of its secoiridoid glycosides.