To study the stability of 2-butenal flavor compounds at different storage conditions, the effects of storage temperature, relative humidity, and the volume content of headspace oxygen on the stability of E-2-methyl-2-butenal, 3-methyl-2-butenal and 2-phenyl-2-butenal were investigated by gas chromatography-mass spectrometry. The results showed that the influence order on the stability of 2-butenals in turn were the volume content of headspace oxygen, the storage temperature, and the relative humidity. After 20 weeks storage at room temperature with air in the headspace of the container, the content of 2-butenals was dropt to 90%. To ensure the quality of 2-butenal, it should be suggested to use within 12 weeks after first opening the container. These three 2-butenals should be less used for formulating the high-temperature-resistant flavorings because they were not resistant to high temperature. Mass spectrum and retention indexes in two different polar chromatographic columns were applied to determine the compounds newly formed during storage. The results showed that E-2-methyl-2-butenal and 3-methyl-2-butenal were easily oxidized to produce E-2-methyl-2-butenoic acid and 3-methyl-2-butenoic acid, respectively. However, 2-methyl-3-phenyl-2-propenoic acid and 1-phenyl-1-propanone were derived from 2-phenyl-2-butenal during storage. The results also indicated that 2-butenal flavor compounds should be preserved at lower temperature and at inert gas atmosphere.