For surface modification, montmorillonite (MMT) was treated with a controlled amount of double octadecyl dimethyl ammonium chloride. The modified montmorillonite were investigated by FTIR、WAXD and SEM. Simultaneously, the organic montmorillonite was modified by different coupling agents twice, and then used the solution intercalation to prepare EVOH/MMT nanocomposite membrane and tested the performance of membrane . The result indicated: the modified montmorillonite clay surface changed from hydrophilic to hydrophobic; The level distance increased 3.5nm from 1.467nm; The composite membranes of EVOH/OMMT which was treated with double octadecyl dimethyl ammonium chloride and 5 % coupling agents KH550 have better improved mechanical and barrier properties; at the same time the transparency of composite films was not affected.