Abstract: In order to probe the chemistry behind quality changes of α, β-unsaturated aldehyde flavors, the chemical compositions of the converted products of seven α, β-unsaturated aldehyde flavor monomers were investigated by GC/MS and as a function of varying storage temperatures. The GC/MS quantitative method was established to quantify the main converted products, α, β-unsaturated acid, and the samples of α, β-unsaturated aldehyde flavor monomers stored in 11 laboratories. The results showed that: 1) This method was simple, highly sensitive (LODs < 0.12 μg/mL) and reproducible (RSDs < 4.5%). 2) The content of α, β-unsaturated acid substances in α, β-unsaturated aldehyde flavor products stored in different laboratories ranged from 15.8 to 450.6 mg/g. The longer the storage time was, the higher the contents were found, which was consistent with the results of the varying temperature experiments. 3) α, β-Unsaturated acid could be used as a marker to monitor the quality change of α, β-unsaturated aldehyde flavors.