Abstract: Oxidative stability is one of the important indexes on evaluating the quality of vegetable oils.Rancidity deterioration decreases the oxidative index significantly.Antioxidant concentration, fatty acids composition, position in triglyceride and triglyceride structure could result in different oxidative stability in oils.Differences of oxidative stability connect to the oxidative index of oils, which may decide the primary and secondary oxidation products is synthesize evaluation to vegetable oils.This article discussed the oxidative mechanisms of oils and assessment of oxidative degree, especially the internal and external factors involved in the process of oil oxidation.Reference values such as improving the oxidative stability related to the production and storage, and taking precaution against damage occurred in the development of oil oxidation were advanced.