The monoterpenes and sesquiterpenes are analysed in the leaf and stem of Chrysanthemum boreale using gas chromaltography-mass spectrometry (GC-MS). The total amount of sesquiterpenes are always higher than monoterpenes in both leaf (2.0-3.4 times) and stem (1.6-8.3 times). The mono- and sesquiterpenes yields of the leaf are higher than the stem. There was no significant difference among the leaf developmental stages, while those of stem were varied. Seventeen monoterpenes and 9 sesquiterpenes compound in this plants comprised more than 5% of the mean total monoterpenes and the total sesquiterpenes in each dates. Among leaf monoterpenes, the concentration of (+)-Limonene and unknown compound no. 13 (Retention time, R.T.=17.28) varied significantly during leaf growing season, and the concentrafion of unknown compound no. 7 (R.T.=35.04) and no. 9(R.T.=35.71) varied in the leaf sesquiterpenes. Similarly the results from the leaf, the concentration of five monoterpenes in stem also varied significantly during maturing period, and much varied in seven compounds of stem sesquiterpene. The major sesquiterpenes of leaf and stem were ${alpha}-Humulene$ and compound no. 2(R.T.=26.19).