Abstract: Effects of nutrient concentrations on the growth and accumulation of exopolysacchrides of spaceflight and non-spaceflight Dunaliella salina were studied.It showed that the optimal combination in concentration of nutrients for their growth was different,because of the complex effects of several space environmental factors.The optimal combinations for the growth of non-spaceflight and spaceflight D.salina were CaCl₂ 200 mg/L,MgCl₂ 500 mg/L,KNO₃ 1000 mg/L,KH₂PO₄ 55 mg/L and CaCl₂ 250 mg/L,MgCl₂ 500 mg/L,KNO₃ 1000 mg/L,KH₂PO₄ 15 mg/L,respectively.The optimal combination for(accumulation) of exopolysacchrides of spaceflight and non-spaceflight D.salina was similar.It was CaCl₂ 250 mg/L,MgCl₂ 2000 mg/L,KNO₃ 500 mg/L,KH₂PO₄ 15 mg/L.The yield of exopolysacchrides of spaceflight D.salina was higher than that of non-spaceflight D.salina.