Abstract: The low gas barrier and water vapor permeability of polyethylene (PE) packaging film limit the regulation of respiratory metabolism and humidity within the packaging environment. Consequently, this can accelerate the aging and mold growth of fruits and vegetables. To enhance the gas barrier properties and water vapor transmission rate of PE bags, in this study, PE served as the base material, with varying amounts of polyhydroxy polymers incorporated. The composite films (P0, P 2, P4, P6, P8) were prepared via melt blending and granulation blow film processes. Their structure, crystallinity, optical properties, mechanical properties, and barrier performance were characterized to identify the optimal formulation for spontaneous modified atmosphere packaging bags. The results indicated that the P4 composite film exhibited increases of 82.38%, 21.46%, and 222.84% in elongation at break (transverse direction), hydrophilicity, and water vapor permeability, respectively, compared to the PE film. Conversely, its carbon dioxide and oxygen permeability decreased by 10.59% and 34.24%, respectively. In summary, the P4 composite film demonstrates excellent gas barrier properties and water vapor permeability. Its composition can readily create an environment characterized by low oxygen, high carbon dioxide, and low humidity, providing a theoretical basis for developing fruit and vegetable preservation films.