Abstract: ObjectiveThe chemical constituents and antioxidant activity of the volatile oil from leaves of Canarium pimela Leenh. in Rong County were studied to provide references for its medicinal development. MethodThe volatile oil was extracted by steam distillation, and then the composition of oil was analyzed by GC-MS. Chromatographic peak area normalization method was used to calculate the relative mass fraction of each ingredient . The DPPH· method was used to study its antioxidant activity . Result55 compounds were isolated and 53 compounds were identified in the leaves that composed about 98.130% of the total volatile oils, in which the ratio of monoterpenoids and sesquiterpenes was relatively higher, 20 and 18 types, respectively. The principal chemical constituents of the volatile oil were ere-mophila-1 (10), 11-diene (11.652%),α-selinene (10.291%), γ-muurolene (9.719%), α-pinene (9.208%) and 1,2,3,4,4a,7-hexahydro-1,6-dimethyl-4-(1-methylethyl)-Naphthalene (7.523%). The scavenging ratio for the DPPH· radicals reached 63% at the concentration of 1 . 2 g/L . ConclusionThere are many chemical constituents in the volatile oil and the main compounds are monoterpenoids. The volatile oil shows certain antioxidant activity and can be further studied as a natural spice and antioxidant.