Abstract: Fermentation of glucose-xylose mixture to ethanol was investigated with Pichia stipitis. The fedbatch was used to increase the useful yield of sugar and rate of ethanol. The results showed that the best conclusion was the initial content of sugar at 94.0 g/L. Then it produced the concentration of ethanol 33.9 g/L for once adding. Prolonging the fermentation for once adding could decrease the residual concentration of sugar and increase the concentration of ethanol. But the less change of sugar, the more concentration of ethanol. The residual concentration of sugar was 9.1 g/L and the concentration of ethanol was 34.3 g/L after the fermentation at the initial sugar concentration of 108.0 g/L for 31 h . The residual sugar was 0.4 g/L and the concentration of ethanol was 37.0 g/L after fermentation for 42 h. To finish adding sugar in 12 h and it was fit for adding sugar twice at the total sugar concentration of 80.9 g/L. And the concentration of ethanol was 33.8 g/L after fermentation for 24 h.