Abstract:Plant volatiles play an very important role in the host orientation of phytophagous insects.Thisstudy aims to explore the volatiles from the host plant Medicago sativa L. and to provide a theoretical basis forscreening plant-originated of Loxostege sticticalis L.The volatile components of Medicago sativa leaves,stemsand flowers were analyzed by headspace solid phase microextraction andgas chromatography-mass spectrometry,and the relative contents of compounds in each part were calculated by ion flow peak area normalizationmethod.The results showed that the leaves,stems and flowers of Medicago sativa included 98 volatile components.The chemical components of volatile substances in each part are similar but the content is significantlydifferent. Among which the chemical components and contents of volatile compounds in Medicago sativa arethe most abundant,with a total of 65 compounds,accounting for 93.69% of the total volatile compounds,followedby leaf volatiles,66 volatile compounds,accounting for 90.42% of the total volatile compounds,the componentsand contents of stem volatiles were relatively fewer,a total of 41 compounds were identified,accountingfor 79.10% of the total volatile compounds. There are 24 kinds of common volatile components in the threeparts,and the high contents are 3-pentanone,2-Methybutan-1-ol,cis-2-penten-1-ol,Trans-3-Hexen-1-ol,4-Methyl-1-penta-nol,tert-butylcyclohexane,α-Pinene,3-Octanol,(3Z)-3-Hexen-1-yl acetate.The results of this studycan provide a theoretical basis for the development of plant source inducers for the control of pests in Medicagosativa L.