Abstract: In order to identify the substances during the maizeing mildew process,the volatile substances were enriched by 50/30 μm DVB/CAR/PDMS non-polar extraction head and PA-85 μm polar extraction head,and identified by gas chromatography-spectrometry. The results showed that some pungent substances,such as 3-Octanone,dihydro-β-ionone,elemene,palmitic acid,3-ethylphenol,and 4-e thylguaiacol,were not detected or detected with low content at early stage of storage stage. But the content of these substances gradually increased after the heating and mildewing. Therefore,detecting these substances could be used for identifying the mildew degree and preventing mildew.