Polyaniline-Na+-montmorillonite（PANI-Na+-MMT）composite material was synthesized by electrochemical polymerization method. Preparation process of aniline- Na+-montmorillonite precursor was discussed in detail. X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical method were used to characterize the composite. XRD result shows that the interlamellar space of Na+-MMT increases obviously after being intercalated by aniline. Moreover, the interlamellar space of Na+-MMT after electropolymerization is bigger than that of pure Na+-MMT, but smaller than that of aniline intercalated Na+-MMT. SEM image shows that the Na+-MMT composite material after electropolymerization becomes denser. The electrocatalytic properties of the PANI-Na+-MMT modified electrode for the electrochemical oxidation of methanol and redox of potassium ferricyanide are excellent.