Objective: To analyze and identify the chemical composition of Dachunxiong Fang by LC-MS. Method :The analysis was performed on an AQCUITY UPLC BEH C18(2.1 mm×100 mm

1.7 μm) column.The mobile phases were acetonitrile and water in gradient elution.ESI source was used and data were acquited in positive and negative mode. Result :The structures of 17 compounds of Dachunxiong Fang were identified by direct comparison with MS and MS2 of Q-TOF

the elemental compositions analysis

the standard substance and the data of the literature. Furthermore

the types of the compounds were phenols

organic acids

phthalides and compounds containg nitrogen. Addition

the mass spectrum characterization of the major chemical composition of Dachunxiong Fang are analyzed. Conclusion :It is a rapid and accurate method that the composition of compound prescription of traditional Chinese medicine can be identified in terms of the separation of ultra high performance liquid chromatography

the accurate molecular weights measured by MS and other information

which can trace to the source of compounds in Dachuanxiong Fang.