The aim of this work is to prepare starch/PVA composite films added nano-sized poly(methyl methacrylate-co-acrylamide) (PMMA-co-AAm) particles and to investigate the mechanical properties, water barrier properties, and soil burial degradation for the films. Composite films were prepared by using corn starch, polyvinyl alcohol (PVA), nano-sized PMMA-co-AAm particles, and additives, i.e., glycerol (GL), xylitol (XL), and citric acid (CA). Nano-sized PMMA-co-AAm particles were synthesized by emulsion polymerization. The results of the evaluation of properties for prepared films indicated that compared with films without PMMA-co-AAm particles, the mechanical properties and water resistance were improved up to 70-400% by the addition of nano-sized PMMA-co-AAm. In addition, the results of the soil burial biodegradation revealed that films added PMMA-co-AAm particles were degraded by about 45-65% after 165 days.