Polypropylene/montmorillonite composite was prepared via melt compounding process. The dispersion of montmorillonite in the composite was analized by XRD (X-ray deffraction) and TEM (Transmission electron microscope). Electronic radiation was applied to make the composite radiation closs-linked in air. The effect of cross-linking agent and montmorillnite on the properties of polypropylene cross-linking was studied. The results indicated that cross-linking did not take place in absence of cross-linking agent, while in presence of both cross-linking agent and montmorillonite polypropylene cross-linking occurred in certain absorbed dose range. The cross-linked polypropylene/momtmorillnite composite exhibited improved mechanical properties.