Abstract: In order to improve the melting phenomenon of gelatin due to poor thermal stability during heating, gelatin was modified with tannic acid to explore the effects of modified gelatin fat substitutes on the structure and functional properties. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), freeze-thaw stability, cooking resistance, water holding capacity and texture properties were used to explore the effects of tannic acid modified gelatin fat substitutes on the structure and functional properties. The results showed that when the pH value was 5, the mass ratio of gelatin to tannic acid was 1.2:1, and heated at 36 ℃ for 30 min, the functional groups between tannic acid and gelatin combined with each other, the two reacted and changed the protein structure of gelatin, and the microstructure changed from dense and uniform mass structure to loose and porous pore structure; Freeze thaw stability and cooking resistance increased, water holding capacity and swelling capacity decreased, hardness and chewability increased, elasticity, cohesion and adhesion decreased, and L^*, a^* and b^* increased. After modification, the thermal stability of gelatin fat substitute was improved, the structural characteristics of gelatin fat substitute were improved, and the product texture was improved, which provided a theoretical basis for the preparation of fat substitute of polyphenol modified gelatin.