In order to improve the efficiency and quality of raw wheat koji fermentation, basing on the traditional production technology of Caobao koji, the raw wheat was cultured and made into imitated Caobao koji with modern temperature and humidity control technology. The enzyme activity and community structure of the two kinds of koji, the physicochemical index and flavor substance content of Huangjiu brewed by the two kinds of koji were compared. Results showed that the enzyme activity of imitated Caobao koji was higher than that of control block koji. And the bacterial community structure was comparable with that in the control block koji, while the relative abundance of fungi in different genera was different.The physical and chemical indexes of Huangjiu fermented by imitated Caobao koji or control block koji had the same changing trend.The alcohol content and amino nitrogen of the Huangjiu brewed with imitated Caobao koji were increased by 4.7% and decreased by 9.6% than those of the control block koji, respectively. And the changing trends about the content of total acid and reducing sugar in both groups was same. The alcohol and ester flavor substances were increased 51.06mg/L and 18.27mg/L than those in the control block koji, respectively.There was no significant difference between aldehydes and acids.Principal component analysis showed that the fermentation performance of imitated Caobao koji was similar to that of control block koji,and the main reason for the significant difference in flavor composition between imitated Caobao koji and control was the addition of cooked wheat koji.