Phosphorus is one of the most important nutritional factors which regulate cell growth and plays a significant role in most cellular processes. It is an essential nutrient element for chlorophyll synthesis it is also a key factor for lipid accumulation in microalgae and protein synthesis. The Effect of different phosphorus sources on the growth and biochemical composition of Nannochloropsis oculata sp. (N. oculata sp.) was investigated in this study. Three treatment (CaH6O9P2) had the lowest total protein 25.90%. Our results suggest that phosphorus sources could influence significantly cell density, dry matter, chl a contents and biochemical composition of N. oculata sp.