Abstract: Microalgae were isolated and purified from the water samples of the Yellow Sea and North coastal water area of Guangxi province in March,2011.The isolated microalgae were cultured and expanded to plot the growth curve,and the content of cellulose,starch and polysaccharide were examined.The result showed that the sample C had the highest growth rate,highest starch accumulation (36.03\%),and relative higher cellulose content,which is likely to be a candidate for industrial application of bio-ethanol in the future.The current study provides a theoretical basis and technical support for the production of bio-ethanol from microalgae.