The authors studied on self oxidation of linoleic acid and the effect of UV irradiation on oxidation of linoleic by Raman spectroscopy.The result reflects that:the intensity of 1 266 cm-1which stands for CH olenic hydrogen in-plane bend is diminished, and it disappeared at 72 hours after the oxidation beginning.That indicates that double bond was lost or reduced. ν(CC) and the carboxylic acid CO vibrations are lies in 1 658 cm-1. The intensity of 1 658 cm-1 was increased in the beginning and decreased then.At the initial stage in the reaction, rearrangement of carbon chains and the formation of carboxylic acids caused the increasing. Later in the reaction, carboxyl of linoleic acid reacted with the generated hydroxy acids, hydroxy aldehyde. So it decreased. UV irradiation accelerated the oxidation reaction starting, increased the speed of the oxidation reaction. All the result shows that the changes of Raman spectroscopy indecate the changes of bulky group in fatty acid oxidation process and the effect of UV irradiation.It provides an effective research tool for the mechanism of lipid peroxidation reaction.