Abstract:The volatile components of sardine oil were differentially analyzed by gas chromatography-ion mobility spectrometry（GC-IMS） during storage at 25 ℃. The results showed that the acid value，peroxide value，anisidine value，and conjugated diene value increased with the storage time. The fatty acid content showed a decreasing trend during the whole storage period. A total of 53 volatile components were obtained from the qualitative analysis，including 8 alcohols，7 esters，10 ketones，18 aldehydes，2 acids，2 ethers，and 6 others. In the sardine oil at the fresh stage，the volatiles such as ethanol，thiophene，and propionaldehyde were the components with high content. In addition，ethyl caproate，which was unique to the early stage，had a refreshing and elegant fruit aroma，and it was the basic substance for the formation of the flavor of the fish oil. Combined with the odor activity value（OAV） analysis，it was concluded that the components that had a significant contribution to the overall flavor of the fish oil were aldehydes （hexanal，heptanal，and butyraldehyde），ketones （2，3-butanedione and 2-butanone），and esters （ethyl pentanoate，ethyl caproate，etc.）. Specifically，aldehydes were the main contributing components.