Microalgae are the natural feeds of many aquaculture species and are the basis of the natural food. This work aimed at the investigation of the possibility cultivation green algae Dunaliella bardawil under outdoor conditions (Egyptian conditions) was studied, variation in chemical composition of algal cells due to season of cultivation was also investigated and costs production. Average cell mass productivity reached the maximum in summer followed by autumn and spring.  The algae were grown in batches using successively larger containers, the yield of the biomass, initial (1.5x10⁶ cells/ml) and final density (12 x10⁶ cells/ml)of  Dunalilla bardawil   were  obtained at four days culture 96 hours.  Methods of drying significantly affected amino acid composition.  Growth and chemical composition of Dunalilla bardawil cells are maximum crude protein content was around 52% for all seasons. Amino acid composition showed no significant difference between the batch cultures. Methionine was the limiting amino acid.  The calculated average and maximum productivity of algal cells and crude protein showed the highest value in summer culture followed by autumn and spring seasons. The chemical composition of the algal powder was similar for all batches in percent of dry weight, 51.8 % crude protein(C.P), 8.9 % ether extract (E.E), 6.5 % crude fiber (C.F), 9.2%  (ash),  23.6% N. free extract (NFE),and algal extracts containing antioxidant vitamins. The high cost of labor in the outdoor cultivation which represents approximately 49.26 % from the total operating costs, followed by the nutrients, which recorded about 26.10 % from the total costs, while the electricity had minimum cost recorded about 24.63 % from the total costs. The harvesting of ton lives algae and oven dried gave 950 g dry biomass. The 1.052 ton live algae produced 1kg dry biomass. The costs of Ingredient outdoor culture for producing  live  Dunalilla bardawil  and operating dry biomass  were about 15.30 Pound \ ton of live algae  and the costs of dry weight were LE 20.30 Pound, while operating costs were LE 21.37 Pound/kg dry biomass.