A series of modified montmorillonites were synthesized from Na-montmorillonite, which included Al-Ti-inorganic montmorillonite and Al-Ti-organic montmorillonite. The optimum Al-Ti and Al-montmorillonite radios were determined. Modified montmorillonites were utilized to treat imitative wastewater and chemical laboratory wastewater and Na-montmorillonite. The effects of optimum conditions such as Al-Ti proportion, pH value of wastewater, throwing amounts of Al-Ti modified montmorillonites and stirring time were investigated. The experimental conditions were optimized with the orthogonal experiment. The results show that the capacity of inorganic montmorillonite and organic montmorillonite is obviously better than that of original montmorillonite in water treatment. The removal rates of colority and turbidity are over 93%. The removal rates of COD are over 66.31% by organic montmorillonite. The result is satisfactory.