Abstract: Co-doped montmorillonite composites with excellent adsorption performance were synthesized by ion exchange method with montmorillonite as basic material.Composites were characterized by X-ray diffraction（XRD），electron diffraction spectrum（EDS），FT-IR，and nitrogen adsorption（BET） techniques.The adsorption mechanism and performance of the composites were discussed and tested.The experiment results indicated that the cobalt was doped into the interlayers of montmorillonite successfully.The adsorption mechanism of composites accorded with Freundlich and Langmuir adsorption models in appropriate methylene blue（MB） concentration.When the mass fraction of cobalt was 5%，he performance of composites was the best，and the specific surface areas and adsorbance of composites reached 176.38 m2/g and 0.399 8 mmol/g，respectively.

Key words: modified material, cobalt, montmorillonite, adsorption mechanism