The effect of temperature on a very high gravity ethanol fermentation using no cook process was investigated. We found that a gradient temperature control strategy could improve the fermentation efficiency significantly. With the assistance of a new raw starch hydrolyzing enzyme and a gradient temperature control strategy, the ethanol concentration could reach up to 20% (V/V) within 90 h using commercially available dry yeast, when sorghum was used as the raw material and the dry substrate concentration was controlled at 35%.