To analyze and identify the blood components of Citri Reticulatae Pericarpium of different aging time by ultra-performance liquid chromatography-quadrupole-electrostatic field orbitrap high resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS).UHPLC-Q-Orbitrap HRMS technology and Compound Discover 3.0 software were used for analysis.The spectrum differences of Citri Reticulatae Pericarpium extract,administered serum,and blank serum were compared,and molecular weight,secondary fragment information,reference literature,and reference substance information were combined to find out the prototype components and metabolites absorbed into the blood after oral administration of Citri Reticulatae Pericarpium liquid.34,24 and 15 components were identified in the blood of 2,4 and 8-year-old Citri Reticulatae Pericarpium,and the content of flavonoids in the blood of 2-year-old Citri Reticulatae Pericarpium was higher than that of 4 and 8-year-old Citri Reticulatae Pericarpium.The UHPLC-Q-Orbitrap HRMS can provide a rapid,accurate and comprehensive analysis of the migrating components in blood after the administration of Citri Reticulatae Pericarpium,which can provide a reference for the later research on the pattern of the substance basis of the medicinal effects of Citri Reticulatae Pericarpium and provide new ideas for the study of the scientific connotation of the older the better of Citri Reticulatae Pericarpium.