Abstract: In order to reduce the amount of HCl used in the hydrated ferrous oxide (HFO) composite adsorbents preparation process, which frequently caused serious equipment corrosion, safe and environmental problems, several adsorbents were prepared with various HCl concentrations. The effectiveness of P adsorption by the adsorbents were investigated at various perspectives, including adsorption kinetics, adsorption isotherms, effect of pH, co-existing ions and desorption methods. Experimental results demonstrate that phosphate adsorption capacity of HFO composite adsorbents doesn’t decrease significantly with the decreasing HCl concentration (from 2 mol·L⁻¹ to 0.5 mol·L⁻¹). The maximum P adsorption capacity of HFO composite adsorbent prepared at 0.5 mol·L⁻¹ HCl is 29.67 mg·g⁻¹, which is higher than the corresponding value of D201 resin (16.39 mg·g⁻¹). The adsorption kinetic curves of the adsorbents are fitted well with the pseudo first order adsorption kinetic equation. The optimal pH for P removal is 6-8. When the concentration of coexisting ions, such as Cl⁻, NO₃⁻, SO₄²⁻, CO₃²⁻, in P solution is 1.0 g·L⁻¹ respectively, the phosphate adsorption of HFO composite adsorbents decreases by 31.1%-53.0%. The adsorbed P on HFO composite adsorbents could be well desorbed with 5wt% NaOH solution.