Al-Cr-pillared montmorillonite was synthesized by using bentonite and Al-Cr pillaring solutionsas starting materials. The basal spacing and specific surface areas of the materials were significantly increased rela-tive to those of untreated clays. When the Al/Cr molar ratio ( R ) was 0.10, the d (001) value and specific surfacearea of pillared montmorillonite were 1.9194 nm and 165.7 m2 g- 1 , respectively. Thermal stability of the mate-rials was determined using calcined tests and X- ray diffraction (XRD) analysis. The materials formed at differentR(0.05;0.10;0.15;0.25) exhibit a high thermal stability at 300℃ , especially at initial R = 0.10, the basalinterlayer spacing of materials is stabilized at 1.7313 nm after calcined at 500℃ for 2 h. Adsorption behavior ofthe materials was studied by adsorption experiments. The results show that the Al- Cr-pillared montmorillonites ex-hibit much stronger adsorption capacity on Cr6+ in aqueous solution than untreated clays do.