Abstract: The total fatty acids, bound and free fatty acids of seed oil from Trichosanthes kirilowii were identified by GC-MS technique together with method of methylation reaction, and the scavenging capacity of free radical were analyzed. The results showed that the seed of T.kirilowii was rich in fatty oil and its oil yield ration could reach 52%, the bound fatty acids (99%) were dominant component in the total fatty acids. Unsaturated fatty acids accounted for 83.3%, the main constituents were Linoleic acid, Oleic acid (9-Octadecenoic acid) and (Z, Z, Z) -9, 12, 15-Octadecenoic acid. The results of antioxidant activities showed that the seed oil had doeseffect relationship in scavenging activities of hydroxyl radical in vitro and the hydroxyl radical scavenging rate of 95.0% was observed at the concentration of 1.0mg/mL. In conclusion, the seed oil of T. kirilowii which was rich in unsaturated bound fatty acids should be a kind of functional edible oils for developing health foods.