With water as solution, ferric chloride (FeCl3∙6H2O) as oxidant, sulfuric acid (SA) as dopant, prepared polypyrrole/montmorillonite (PPy/MMT) via chemical oxidation polymerization. We researched the effect that the content of the polypyrrole to the conductivity of composite in the condition of n (Py): n (FeCl3∙6H2O): n (SA) =1: 1: 0.5. Using IR, XRD, IR, TEM and SEM modern characterization methods to characterize internal structure of composites, the results show PPy were intercalated into the inner space of MMT. The surfaces of MMT intercalated are coated by conductive polypyrrole particles with equal size and uniform arrangement. MMT dispersed among conductive polypyrrole matrix and overlapped each other, which formed a conductive network. Using percolation theory, we analyzed the conductivity of composites that conform to the classical statistical percolation theory.