Salinity imposes significant stresses in various living organisms including microalgae. Under favourable and unlimited growth conditions microalgae produce primarily polar lipids, which enrich chloroplast and cellular membranes. However, under unfavourable growth conditions microalgae accumulate neutral lipids in lipid droplets located in the cytoplasm. The study focuses on the effect of salinity concentrations on the cell growth, photosynthetic pigments and some metabolic activities as carbohydrate, protein, lipid, total amino acids, proline, choline, glycine betaine and individual's fatty acids in Anabaena fertilissma by setting up different ranges of salinity (2.5, 5, 10, 15 and 20‰). The results were as follows. The microalga was able to tolerate the salinity levels, algal cell division showed a good adaptation to the highest salinities and cells would not go into osmotic shock and die, where the changes in salinity have significant effects on the growth. The growth and photosynthetic pigments tends to decline as salinity increases. While increased of protein, carbohydrate, lipid, proline, choline and glycine betaine. The composition of fatty acid methyl ester has been identified as C16:0, C18:0, C20:0, C16:1, C18:1, C18:2, C18:3, C20:4, C20:5 and C22:6. It is clear that the effects of salt stress on the proportional amounts of fatty acids.