Abstract: In order to improve the deficiency of mild-flavour fuqu baijiu, such as spicy, unmellow and soft flavor, Saccharomycopsis fibuligera was used in production to improve the quality of the original baijiu. Two kinds of Saccharomycopsis fibuligeras fuqu (Saccharomycopsis fibuligera T(NT), Saccharomycopsis fibuligera L(NL)) were prepared in the test. Sensory evaluation, flavor substance analysis, acid production capacity, saccharification power and fermentation power analysis of fuqu were conducted. The fuqu were applied in the brewing production of mild-flavour fuqu baijiu. The cereal baijiu yield rate, tasting substances of the original baijiu were analysed and their sensory quality of original baijiu were evaluated. The results showed that NL fuqu smelled creamy, floral. The floral fragrance was more obvious. NT fuqu smelled creamy, koji aroma. The koji aroma was more obvious. The contents of esters, ketones and acids of NL fuqu were 6.56%, 16.59% and 32.28% higher than that of NT fuqu, respectively, but the contents of aldehydes and alcohols were 5.67% and 2.67% lower than that of NT fuqu, respectively. Both fuqu had certain acid production ability, saccharification ability and fermentation ability. Compared with the control, the average baijiu yield rate of all test schemes was higher than that of the control under different test conditions, and the average baijiu yield rate of scheme 1 was the highest, which was about 4.62% higher than that of the control. The experimental schemes increased the sweetness of the original baijiu and the quality of base baijiu was also improved. The scheme had the value of popularization and application.