Abstract: Cudrania tricuspidata (Carr.) Bur is a traditional Chinese medicine used in the treatment of hepatitis, rheumatism, jaundice, acne, dysmenorrhea, and chronic gastritis. The chemical components of Cudrania tricuspidata (Carr.) Bur were obtained using the traditional method of extraction and separation. In this study, single-stage mass analysis that supplied molecular weight information was developed by a linear ion trap quadrupole-Orbitrap-mass spectrometry (LTQ-Orbitrap MS) and structural information was provided by multi-stage mass analysis. LC/MS technology was used to rapidly identify the chemical components of Cudrania tricuspidata (Carr.) Bur. The chromatographic separation was performed on a C18 column (4.6 mm×150 mm×5 μm). Gradient elution of water (containing 0.1% formic acid) acetonitrile was used as the mobile phase. ESI-MS analysis was operated in the range of m/z 100-1 000 at negative ion mode. Based on the accuracy of the relative molecular mass, fragment ions, retention behavior compared to the database, a total of 45 components were identified, including 28 flavonoids, 11 xanthones and 6 other components, while 2 compounds were firstly found in Cudrania tricuspidata (Carr.) Bur. It is an effective method to provide chemical information concerning the constituents in herbal medicines, which can be helpful for the quality control and further phytochemical studies of Cudrania tricuspidata (Carr.) Bur, but the method is impossible to determine the isomers and steric structures, and some small non polar compounds can not be detected due to the lack of cleavable groups.