Adsorption of heavy metal Cd (II) by brown algae Sargassum myriocystum was examined to appraise the usefulness of biomass to eliminate heavy metals from environment. Different optimizing conditions such as contact time, biomass dosage, solution pH, temperature, and initial Cd (II) concentration was examined by batch studies. The most favorable environment was (1 h, 100, 150 and 200 rpm shaking speed, 25 °C, pH = 5 with heavy metal cadmium 50 mg/L, 100 mg/L, 150 mg/L and 200 mg/L). Several kinetic and isotherm models are used to distinguish the Cd (II) sorption method against biomass. Kinetic studies used in this biosorption method, are Pseudo first and Second order, Elovich model as well as Intra-particle diffusion models. Langmuir and Freundlich isotherms models were tested for modeling the adsorption isotherms. The separation factor R_L and surfacecoverage