Inducing yeast cells to self-flocculate could be considered a cell immobilization method. The growth kinetics of the flocs from Schizosaccharomyces pombe was studied in an experimental suspended-bed bioreactor with starch hydrolysate obtained by two-stage enzymatic hydrolysis. It was discovered that a limited oxygen supply was necessary during continuous ethanol fermentation with yeast flocs. The oxygen supplied was a kind of limited substrate effecting on the floc growth. Further, a kinetic model describing this floc growth was proposed.