Abstract: The seed oil of Malania oleifera in Guangnan, Wenshan, Yunnan were extracted, antioxidant activity of the seed oil were tested, then constituents with antioxidant activity were separated and identified. The results showed that seed oil of Malania oleifera had a certain degree of scavenging activity on DPPH·radical, it was relatively weaker compared with olive oil. 100mg/mL seed oil of Malania oleifera could clear approximately 50% DPPH·radical. There were two chemical compounds in the seed oil of Malania oleifera with the capacity of antioxidant, those two chemical compounds were confirmed as linoleic acid and palmitic acid via GCMS analysis, and their antioxidant activity were weaker than VC.