Objective: This study aimed to conduct a qualitative analysis on chemical components in water extract of Epimedii Folium by high performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry(HPLC-ESI-Q-TOF-MS). Method: LC-MS-MS was adopted

using C18(4.6 mm×250 mm

5 μm) column with methanol-0.1%formic acid as the mobile phase for gradient elution;ESI ion source was used for mass spectra

and data were collected in positive and negative mode. Result: Ten compounds from water extract of Epimedii Folium were identified by analyzing positive and negative ion mass spectra information and element composition

and comparing controls of data from relevant literatures. Conclusion: After the separation by ultra high performance liquid chromatography

relative molecular mass was determined by mass spectra

and chemical compounds in water extract of Epimedii Folium were determined by information search through relevant literature data

in order to provide powerful therapeutic material basis for water extract of Epimedii Folium.