In this research the wastewater used as alternative for culture media of cultivation of Chlorella vulgaris. Different conditions were used to study their effect on growth of Chlorella vulgaris such as temperatures with range (20-35̊C), pH (5-11), moreover cultivation time (1-13 day) and dilution ratio (25%-100%). The experimental runs of this work were designed by (Taguchi method). The analyses of Signal to Noise ratio(S/N) and variance (ANOVA) were used to identify the effect and the significance of the process parameters on growth algal. The final results show the significance of all process conditions on growth algae. The order of significance of these conditions is: cultivation time˃ dilution ratio˃ temperatures˃ pH. The moderate temperature at 30̊C, dilution rate at 75%, alkaline conditions at pH=9 and 13 day for cultivation are optimum conditions to enhance the growth algal and to obtaining on high optical density with (0.5997).