To improve the fundamental properties and enhance the functionality of gelatin films, a dual crosslinking strategy was employed to modify gelatin by synergistically incorporating phytic acid ( PA) and calcium ascorbate (CA), with composite films fabricated via solution casting method. SEM, FT-IR and XRD analyse confirmed the synergistic crosslinking interaction of PA and CA within the gelatin networks. The comprehensive properties of the composite films were systematically investigated through tensile tests, UV-vis spectroscopy, water vapor permeability ( WVP) measurements, thermogravimetric analysis, and DPPH radical scavenging assays. Results demonstrate that the incorporation of PA significantly enhances the mechanical and barrier properties of gelatin films. Compared with pure gelatin film, the optimized composite film exhibits a 37% increase in the maximum tensile strength (64.17 MPa) and a 28.3% reduction in WVP. The supplementation of CA not only improves the thermal stability and UV-blocking performance, but also endows the film with remarkable antioxidant activity. The initial decomposition temperature of the composite film increases to 294.8 ℃, and complete UV shielding capacity is achieved for wavelengths below 350 nm. Moreover, 76.9% DPPH radical scavenging activity is attained. The synergistic modification with PA and CA effectively improves the overall performance of gelatin films, providing a technical foundation for developing gelatin-based composite functional films.