Abstract: Simultaneous saccharification and fermentation(SSF) and its advantage were briefly introduced.The recent progress in the process parameters,process flow and fermentative microbe were reviewed.Intensively,the breeding of thermotolerant yeast and its application in the production of bio-ethanol with SSF process were introduced.This might be the most important method to solve the problem of the incoordination in optimal temperature of cellulose hydrolysis and microorganism fermenting of SSF.