Abstract:rans fatty acids are occurring in the process of vegetable oil treated with partial hydrogenation， so usually is also known as hydrogenated vegetable oil. It is often used in processed foods and restaurant， to im－ prove the taste and extend the shelf life or spice， etc. Existing studies have shown that trans fatty acids is related with cardiovascular disease， type Ⅱ diabetes， infant development， etc. The definition， resource， main harm， limit standards at home and abroad， analytical method of trans fatty acid were reviewed in this paper.