Ultra high performance liquid chromatography (UPLC) employs 1.7 μm porous particles resulting in higher peak capacity, better resolution and sensitivity compared with traditional HPLC, and has been applied in many researches.Time-of-flight mass spectrometry (TOF-MS), allows the generation of mass information with greater accuracy and precision.These accurately measured mass values can then be used to produce candidate empirical formulae which significantly reduce the number of possible structures of putative compounds.The application of this approach in separation and identification of soybean soponins hydrolyzed by Aspergillus sp.848s was studied in this paper.