The volatile flavor profile of Daqu is very complex.Many factors including fermentation temperature and fermentation time have great effect on the flavor of Daqu.The volatile flavor of Daqu can be integrated with Chinese liquor to form different flavor of Chinese liquor.In order to understand the optimum time of using Daqu for Chinese liquor brewing on the basis of the volatile compounds,we studied the changes in volatile compounds of Daqu during fermentation and storage by headspace solid phase microextraction(HS-SPME) combined with gas chromatography-mass spectrum(GC-MS).Most volatile flavor increased progressively for the first five days of fermentation,decreased gradually starting the sixth day,and stabilized after 20 days.Nitrogen-containing compounds were increased from the fifth day to the ninth day of fermentation,stabilized after 20 days.The results provide some useful information for improving the processing and quality of Daqu and Chinese liquor.