In recent years, ethanol has attracted much attention as a renewable biofuel because that its blending with gasoline can reduce the emission of pollutants such as CO in combustion. Ethanol is mainly produced by yeast fermentation in industry. For the purpose of increasing the fermentation rate, our institute are cooperating with the ACS, a Germany company, to study a novel fermentation process with yeast recovery and reuse. A demonstration system has been set up in our laboratory. With high-density culture, combined with evaporation of ethanol on line and yeast recycle, the total fermentation time in this process can be reduced to less than 10 hours, and meanwhile, the ethanol concentration of the final fermentation mash could be more than 10%.