Abstract: The effects of different heat treatment temperatures (75, 80, 85, 90, 95 ℃) on the embedding rate, particle size, zeta, secondary structure, tertiary structure and its digestibility in vitro of soybean protein isolate-curcumin complexes were studied in order to explore the structure and interaction mechanism of complexes. The results showed that heat treatment at 85 ℃ was the best to combine soybean protein isolate with curcumin. Meanwhile, the embedding rate reached 89.13%, the particle size was 163.33 nm, and the potential value was −24.30 mV. The total sulfhydryl group and surface hydrophobicity of complex reached the maximum, 3.82 μmol/g and 3814±20, which indicated that the protein structure was stretch to stable and interact with curcumin to improve the digestibility in vitro. It was also concluded that the binding effect of soybean protein isolate and curcumin was enhanced by heat treatment. The result would be beneficial to the innovation and development of soybean protein isolate and curcumin complex.