Abstract: Soy protein isolate and its major components (7S, 11S globulin ) were separated and purified from soybean in the experiments. The protein were heated in order to evaluate the effect of protein denaturation on stability, activity index of protein stabilised-emulsion. The EAI and ESI of SPI and 11S increased and the EAI and ESI of 7S decreased after 95℃ for 5min. Protein was denaturated in different degree after heating, lead to protein structure changed and protein emulsification changed, affecting the emulsion properties.