This aim of this paper is to research on culturing marine algae with high efficiency.Using microalgae Isochrysis Galbana as a model organism,a rapid growth regularity of microalgae in 4.5-L bioreactor was discovered under optimized culture condition,namely,specific growth rates of microalgae from the fourth day to the seventh day at maximum phase (631~905×104 cells·mL-1·day-1).Accordingly,a renewable model of culture microalgae was proposed,namely,at the end of exponential growth,microalgae of 2-L was taken from the bioreactor of 4.5-L,and then sterile natural seawater (SNSW) of 2-L was added into the bioreactor with remaining microalgae of 2-L,now microalgae density was approximately 1800 × 104 cells/mL,with which Isochrysis Galbana will grow under maximum specific growth rate.After two days,density of microalgae reached to 4000 × 104 cells/mL.We repeated the culture process of 2 day three times.Compared with the traditional model of culture microalgae,more than 42% microalgae biomass in per day was obtained in a 4.5-L bioreactor through the renewable culture.Here the renewable model of culture microalgae offered great potential for supplying raw materials of microalgae bioenergy.