With three Saccharomyces cerevisiae strains collected by Institute of Modern Brewing Apparatus and Technology of Qilu University of Technology as experimental materials,an excellent S.cerevisiae strain,R2-b,was selected by the plate separation culture method through the selection of separation medium,observation of appearance of yeast colonies,cell morphology and cell size,and the determination of cell death rate,diacetyl content,reducing power and fermentation power.The yeast strain can meet the demand for fermentation of fresh beer.