The volatile oil in flowers of Dendranthema morifolium (Ramat)Tzvel. cv. Gongju was extracted with steam distillation, the constituents and contents of volatile oil were analyzed by means of GC-MS-DS techniques. The result shows that the principle constituentsof the volatile oil are bicyclo[ 3. 1. 1 ] hept-2-en-4-ol, 2,6,6-trimethyl-, acetate( 39. 64%); benzene,1( 1,5-dimethyl-4-hexenyl) -4-methyl-,2-heptene( 5. 24%); n-hexadecanoic acid( 4. 77%);cis-lanceol( 4. 73%); acetic acid, 1,7, 7-trimethyl-bicyclo[ 2. 2. 1] hept-2-yl-ester(3. 95%);(-) spathulenol ( 3. 38%);2, 4, 6-trimethyl-3-cyclohexene-1carboxaldehyde( 3. 22%); caryophyllene oxide( 2. 88%);1, 2, 3, 4, 5, 6, 7, 8-octahydro-1, 4-dimethyl-7-( 1-methylethenyl) -, azulene (2. 80%);3-(1, 5-dimethyl-4-hexenyl) -6-methylene, cyclohexaene(2. 50%);decahydro-1, 4a-dimethyl-7-(1methylidene) -,1-naphthalenol( 2. 39%); 1,1,2-trimethyl-3,5-bis( 1-methylethenyl) -,cyclohexane( 2. 23%) , etc.