Abstract: Flavonoids of Epimedium truncatum were extracted by ultrasonic assisted extraction with 70% ethanol.The extract was analyzed by capillary liquid chromatography-mass spectrometry,and the main active compounds were determined by HPLC and compared with that of Epimedium sagittatum.Six constituents,including epimedin B,epimedin C,icariin,quercetin-3-O-rhamnoside,kaempferin and 3,5,7-Trihydroxyl-4'-methoxyl-8-prenylflavone-3-O-α-L-rhamno-pyranosyl-(1→2)-α-L-rhamnopyranoside,were isolated and identified from leaves of E.truncatum for the first time.Leaves of E.truncatum contained high levels of epimedin C,which exceeded that of E.sagittatum significantly.Results showed that LC-MS was a quick and easy method for compound analysis of herba epimedii.E.truncatum is a good plant resource for epimedin C and worth further exploration.