The effects of temperature, time, inoculating quantity and dosage of cellulose enzyme on the preparation of fuel ethanol from straw stalks by means of the simultaneous saccharification and fermentation method (SSF) were studied. The results show that after pretreating straw stalk by mechanical comminution and sparse sulfuric acid, the optimal fermenting temperature is 38 ℃, the fermenting period is 72 h, the inoculating quantity is 10%, the dosage of cellulose enzyme is 40 IU/g, and the ratio of Pachysolen tannophilu to saccharomyces cerevisiae is 2∶1. The ethanol yield reaches as high as 0.20 g/g.