Zein exhibits excellent biodegradability, thermal stability, UV resistance, and water barrier properties, making it a promising candidate for food packaging applications. However, pure zein films suffer from brittleness and poor mechanical strength, which limit their practical use. In this study, a unique bilayer packaging film (ZP/P-C) was developed using a layer-by-layer solution casting technique, where hydrophobic zein was coated onto a polyvinyl alcohol and chitosan composite layer (P-C). Incorporating PEG400 into the zein layer improved the interfacial compatibility of the bilayer film, increasing its uniformity and toughness. The resulting bilayer films demonstrated enhanced mechanical properties, flexibility, and water vapor barrier performance. Specifically, the ZP