Abstract: The study aimed to investigate the influence of chitosan particles loaded with sodium sulfate on the structure and properties of the gelatin films by using gelatin as the film-forming matrix and adding chitosan particles loaded with sodium sulfate to prepare composite gelatin films. The thickness, hydration properties, barrier properties, mechanical properties, optical properties, thermal stability and oxidation resistance of the gelatin films were measured, and its structure was characterized. The results showed that the addition of chitosan particles loaded with sodium sulfate significantly decreased the thickness (P<0.05), significantly increased the swelling rate (P<0.05), decreased the dissolution rate from 79.41% to 18.21%, increased the tensile strength from 79.10 MPa to 128.96 MPa, increased the opacity from 3.75 to 6.77, improved the thermal stability, and increased the DPPH radical scavenging capacity from 14.41% to 65.05% of the gelatin films. However, there were no significant changes in the water vapor permeability and elongation at break of the gelatin films. In addition, there was a high compatibility between chitosan particles loaded with sodium sulfate and gelatin molecules, and the addition of chitosan particles loaded with sodium sulfate changed the structure of gelatin films. In conclusion, the incorporation of chitosan particles loaded with sodium sulfate can change the structure of gelatin films to some extent and improve the properties of gelatin films. This study provides theoretical guidance and data reference for the preparation and application of antioxidant composite gelatin films.