Effects of nitrate feeding on the cell growth and lipid accumulation of marine microalgae Isochrysis zhangjiangensis were investigated. When nitrate was supplied at interval of 24h, instead of 72h, a high lipid content of 40.9% and a biomass density of 3.1gL-1 were obtained. To confirm whether I. zhangjiangensis accumulates lipid during nitrogen-repletion, a two-stage cultivation method was applied. This algal strain had a high lipid content during sustained nitrate addition and showed a high carbohydrate content under nitrate-depletion conditions. These results revealed that this algal strain can accumulate lipids under nitrogen-repletion conditions and accumulate carbohydrate under nitrogen-depletion conditions. When cultured in an extremely high nitrate concentration, 9gL-1 at 24h intervals, the growth of algal cells was suppressed, but the highest lipid content of 53% was attained. This special characteristic of lipid accumulation makes I. zhangjiangensis an ideal candidate for producing biodiesel using N-rich wastewater.