Plants contain many kinds of volatile and semivolatile chemicals which play an important role in their life cycles.The chemicals not only exist in the each developing stage of plant,but also distribute in different parts of plant with different chemical composition and amount.The components contained in the different plant parts of Prunella vulgiaris were analyzed by GP-MSE (gas purge microsyringe extraction) coupled with gas chromatography mass spectrometry (GC-MS) technology,and the results were used for comparision of their chemical profiles.The species of compounds determined were 99,93,79 and 66 from the branches,roots,leaves and flowers of Prunella vulgiaris,respectively.And 90,78,79 and 95％ of chemicals were identified,respectively.The major chemicals included alcohols (3.32 ～ 21.27％),aldehyde (5.04 ~ 23.81％),ketones (0.08 ~ 0.83％),alkenes (3.67 ~ 6.93％),heterocyclic compounds (1.51 ~ 3.63％).Among them,the fifteen components such as phenol,2,3-dihydrobenzofuran,1,3-dimethoxy-2-hydroxybenzene and fatty acid were the general chemicals in the four different parts of Prunella vulgaris.1,2,4-Trimethoxybenzene,trans-Isoeugenol,Germacrene and 2,6-Dihydroxyacetophenone were specific component for the branches,roots,leaves and flowers part,respectively.And them were considered being an molecular marker of corresponding parts.