Incorporating polysaccharide-based composite films with nanobiotechnology offers a new strategy for food preservation. This study initially focuses on the preparation of tea polyphenol nanoparticles (TPNP), novel and derived from natural antibacterial agents, which serve to improve stability. Afterwards chitosan-based composite films loaded with TPNP (CTN film) were developed using solution casting method. The incorporation of TPNP significantly improved the UV/water/oxygen barrier properties, mechanical properties and thermal stability, alongside notable physical properties including water contact angle (93.65 ± 0.04°), low water vapor permeability (33.72 ± 3.32 g/m