Abstract: The effects of soy protein as a nutritional additive used in wheat dough on physical properties of wheat dough and baking properties of breadwere explored. Different kinds of soy protein powder, including soy protein isolates, heat-treated full-fat soy protein powder, enzyme-active full-fat soy protein powder, enzyme-active defatted soy protein powder and heat-treated defatted soy protein powder, were used and wheat dough properties such as farinographic, extension and baking properties were investigated. Results show that water adsorption ability of wheat flour is significantly correlative with the nitrogensolubility index of soy protein powder. The extension properties of wheat dough are remarkably affected by the additive quantities of soy protein powder. Adding soy protein powder can decrease the specific volume of bread(significantly correlativewith extension properties of wheat dough, and the firmness of bread crumb, especially of those enzyme-active full-fat soy protein powder. Small quantity of soy protein powder adding(3% of wheat flour) cannot change the sensory propertiesof bread, large quantity of soy flour adding(exceeding 7% of wheat flour) can lead to stickiness and leguminous flavor.