Abstract: The adsoption removal of Cr(Ⅵ) in aqueous solution and the adsorption isotherm and adsoption mechanism were studied with C₂₁H₃₈NBr modified clinoptilolite used as a water treatment material.The result showed that after 30 min adsorption treatment at 25℃,the removal rate of Cr(Ⅵ) in aqueous solution surpassed 93% under treatment conditions of modified clinoptilolite particle size of 0.25-0.38 mm,clinoptilolite concentration of 30 g·L^-1 at the initial pH=6.The adsorption of Cr(Ⅵ) to modified clinoptilolite could be expressed with Langmiur adsorption isotherm.The saturated adsorption amount of Cr(Ⅵ) reached 36.78 mg per 100 g with modified clinoptilolite.By comparing the XRD spectra of the modified clinoptilolite and the unmodified clinoptilolite,C₂₁H₃₈NBr could be found in the modified clinoptilolite.IR analysis indicated that the adsorption removal of Cr(Ⅵ) by modified clinoptilolite was the function of C₂₁H₃₈NBr in the modified clinoptilolite.