Abstract: Rubus aleaefolius Poir.(Rosaceae), "Cu Ye Xuan Gou Zi", is used as Chinese medicine to treat liver injury and cancer in the south of China.Polyphenols and triterpenoids in its leaves were analyzed by high performance liquid chromatography coupled with diode-array detector and tandem mass spectrometry.Compound structures were tentatively identified by comparing ultraviolet (UV) spectra and mass spectra with those of certain authentic samples and literature.Eighteen compounds were analyzed in the leaves of R.aleaefolius, among which two polyphenols were definitely identified, and nine polyphenols and seven triterpenoids were tentatively identified.Additionally, fragmentation patterns of main fragment ions for triterpenoids in negative ion mode were proposed and summarized.According to these patterns, a triterpenoid, 3-O-p-coumaroyl-19α-hydroxyursolic acid was tentatively identified.Rutin, chlorogenic acid and 3-O-p-coumaroyl-19α-hydroxyursolic acid were reported in the R.aleaefolius leaves for the first time.