On the basis of modifying Na-montmorillonite with single-chain quaternary ammonium, prepared secondarily-intercalated montmorillonite by double-stranded quaternary ammonium.The influence of different cation exchange capacity (CEC) of agents on the organic intercalation was explored. The prepared samples were characterized by the X-ray diffraction, Fourier-transform infrared and thermo gravimetric differential thermal analysis. Results show that the basal spacing of secondarily-intercalated montmorillonite increased with the CEC of intercalation agents, and double-stranded quaternary ammonium was intercalated into the montmorillonite, which played an important role in the increasing of interlamellar space.