A new type of water treatment agent, aluminum-magnesium hydro xide positive nanomaterial(AMH)is introduced.The adsorption perfo rmance of Cr(Ⅵ)on AMH and the effect of the adsorption time, pH,SO₄^2- and Cr(Ⅵ )concentration on the adsoption have been studied.The result s of static test show that the adsorption equilibrium is reached within 4 minutes, the adsorption efficiency is higher in the range of pH 5 ～7,the adsorption amount increases steadily along with the concentration of Cr(Ⅵ )and the maximum adsorption amount is 110 mg/g, SO₄^2- has no influence on the adsorption.The adsorption is other maccords with Freundlich mode.The adsorption mechanism is mainly of ions exchange adsorption.Cr(Ⅵ)is adsorbed chiefly in the form of Cr₂O₇^2-.The particulate adsorbent of AMH is made by silica gel method.The dynamic test indicates that the saturated adsorption amount of the particulate adso rbent is 1.96 mg/g for the chromium-containing wastewater of 100 mg/L.The adsorbent can be regenerated with the acidic solution of 0.2 mol/L FeCl₂.