Abstract: Triterpene and saponin in Radix ilicis pubescentis were identificated by HPLC-MS. The samlpe was extracted with methanol, and analyzed by HPLC-IT-MS and HPLC-TOF-MS to obtain the positive-ion and negative-ion MS¹ and MS² spectra together with extract molecular weights. Night triterpenoid saponins were identified, and two of them were confirmed by reference substances. The ESI-MS characteristic of triterpene and saponin in Radix ilicis pubescentis was summarized, and the proposed fragmentation mechanism based on ilexgenin A was illustrated.