In order to treat wastewater containing Cr(Ⅵ)by Enteromorpha prolifera, hydrochloric acid was used to modify Enteromorpha prolifera. The effects of pH value, dosage of hydrochloric acid modified Enteromorpha prolifera, adsorption time and temperature on the adsorption of Cr(Ⅵ)by hydrochloric acid modified Enteromorpha prolifera were studied through batch adsorption tests. The results show that the method of remoⅥng Cr(Ⅵ)from wastewater by using hydrochloric acid modified Enteromorpha prolifera as adsorbent is feasible. The acidic condition is conducive to the adsorption of Cr(Ⅵ). When the initial mass concentration of Cr(Ⅵ)is 100 mg/L and the pH value is 1, the removal rate can reach 99. 7%. The quasi-second-order dynamic equation can better fit the experimental data. The effect of diffusion resistance in particles is more significant than that of external mass transfer resistance. The adsorption isotherm data are more consistent with Langmuir model. The Gibbs free energy of adsorption is negative while the enthalpy of adsorption is positive. The adsorption of Cr(Ⅵ)by hydrochloric acid modified Enteromorpha prolifera adsorbent is a spontaneous endothermic process.