【Summary Description】Abstract: The pyrolysis reactions of Dioscorea opposita L. at 300, 400, 450, and 500 ℃ were investigated using capillary gas chromatography mass spectrometry. The pyrolysis products of Dioscorea opposita L. were analyzed, and it was found for the first time that there was caffeine in the pyrolysis products. It was confirmed that the caffeine component was produced by the decomposition of chemical components in Dioscorea opposita L