In order to explore the effects of different nitrogen sources and concentrations on the growth and biochemical composition of marine seawater-acclimated algae Asterarcys sp. SCSIO-44020,three nitrogen concentrations（3,6 and 18 mmol/L）of three nitrogen sources（sodium nitrate,urea and ammonium bicarbonate）were added to 30‰ seawater ZSNT based medium. Results showed that the biomass concentration of Asterarcys sp. increased with the increase of nitrogen concentration. At 18 mmol/L,the highest biomass concentration（7.78 g/L）was obtained with sodium nitrate as nitrogen source,followed by urea（6.61 g/L）,and the lowest was obtained with ammonium bicarbonate（5.33 g/L）. Nitrogen limitation was beneficial to the accumulation of lipid and carbohydrates of algae cell,and the maximum lipid content and carbohydrates content reached 46.78% DW（ammonium bicarbonate,3.0 mmol/L）and 29.70% DW（urea,3.0 mmol/L）respectively. The results also showed that the ratio of neutral lipid was very high（≥82.58%）,and it increased with the decrease of nitrogen concentration under three nitrogen sources. The fatty acid composition of the Asterarcys sp. mainly included C16:0（palmitic acid）,C16:1（palmitoleic acid）,C18:0（stearic acid）,C18:1（oleic acid）,C18:2（linoleic acid）and C18:3（α-linolenic acid）,in which the content of oleic acid was the highest（38.75% of total fatty acid）. The high nitrogen was beneficial to the protein accumulation,and the protein content of Asterarcys sp. was the highest（17.61% DW）under the condition of 18 mmol/L urea as nitrogen source with sufficient nitrogen. The maximum production of total lipid,total carbohydrates,total protein and total carotenoids in this microalga was obtained at 18 mmol/L using sodium nitrate,which was 2.79,1.71,1.22,and 30.29 mg/L,respectively. Therefore,Asterarcys sp. SCSIO-44020 grew well in seawater,and high concentration（18 mmol/L）of sodium nitrate was initially determined as the optimal nitrogen source for its cultivation in column glass photobioreactor.
