Aiming at the advanced purification of low concentration of phosphorus in natural water, the adsorption of phosphate by CaO₂ was studied using the models of adsorption kinetics and adsorption isotherm, and the influence of different operating parameters on the phosphorus removal was investigated.The results showed that:(1) The experimental data for the process of phosphate uptake onto CaO₂ fit the Langmuir isotherm mode, and the maximum adsorption capacity was 381.7 mg/g (25℃).(2) Thermodynamic parameters in the process of phosphorus removal are ΔG⁰<0 and ΔH⁰<0, while the process was a spontaneous exothermic one.(3) The adsorption performance of CaO₂ was evaluated by the pseudo-second-order reaction rate equation, when the adsorption rate increased with the increasing concentration of phosphate in the solution, and the adsorptive reaction reached equilibrium in 4 minutes.(4) The optimized effect of phosphorus removal was obtained at pH=8.(5) Among the high concentrations of coexisting anions, the CO₃^2- expressed the greatest influence on phosphorus removal of CaO₂ and could make the adsorption capacity reduce 14.7% under the concentration of 10 times.