Abstract: The volatile oil from C.odorata had a significant effect on the growth of plants, fungi and insects. The result showed that the seedling growth of five test plants was obviously inhibited,in the order of ryegrass>Chinese cabbage>radish>snap been>rice. The inhibitory effect of the oil at its middle concentration (800 mg·L^-1) for Pyricularia grisea was the strongest, the next was to Phytophthora nicotianae, and the weakest was to Fusarium oxysporum . The inhibitory percentage was 61.40%, 29.27% and 14.44%,respectively. The volatile oil from C. odorata at the dose of 10～20 μl·plant^-1 had a significant oviposition deterrent effect on Phyllotreta striolata and Plutella xylostella .The volatile oil from C.odorata was analyzed by GC/MS and thirty components were identified. Terpenoids compounds were major components of the volatile oil, such as trans caryophyllene (16.58 %),δ-cadinene (15.85 %), α-copaene (11.58%), caryophyllene oxide (9.63 %), germacrene D (4.96 %) and α-humulene (4.32 %).