Starch/soybean residue composite foam cushioning material with montmorillonite contents were prepared by a melt-intercalation method. The characterization of the nano-composites was analyzed. The results showed that there is little difference on the expansion rate when montmorillonite content is lower than 3%; when montmorillonite content is above 3%, the expansion rate decreases remarkably with montmorillonite content; the apparent density of the composite with 3% montmorillonite content is lowest; the one with 5% content has the smallest cell diameter, has even cell distribution, and has good effect to resist to water absorption; addition of MMT can increase the mechanical strength of the composite dramatically and the 5% MMT content has the highest compressive strength; among the four MMT content nanocomposites, the 5% one has the highest comprehensive properties.