Abstract: In this study, epigallocatechin gallate（EGCG） was added during heat-or enzyme-induced soy proteins isolation（SPI） gels formation process to prepare an EGCG/SPI gel system, aiming to improve the gel strength. The surface hydrophobicity, free sulfhydryl content, endogenous fluorescence spectroscopy and circular dichroism spectroscopy of SPI was employed to analyze the SPI structural changes, and the results showed that EGCG addition could improve the surface hydrophobicity and free sulfhydryl contents of SPI, which could unfold protein chains and present properties of slack, stretch and increased molecular flexibility. Besides, the disordered structural（β-turns and random coils） contents of SPI were increased significantly, while the content of β-sheets was obviously decreased after EGCG addition. Moreover, the chemical force, gel strength, rheological properties, water holding capacity and the surface topography changes of EGCG/SPI gel system were further studied. Results showed that the EGCG addition could enhance the hydrogen bonding, hydrophobic interactions and disulfide bonding in thermal gel, and improve the water holding capacity, gel strength and storage modulus with a tighter three-dimensional network structure.