In order to research the effect of soy protein and its modified products on the quality of steamed bread， soybean proteins were added into flour in different ratio， texture properties， sensory evaluating value and physicochemical properties of the steamed bread， and the properties of flour and dough were determined. The results showed that dough development time and dough stability increased by 2.5 min after adding 1.5%， and that of adding 4.5% TSP dough increased by 1 min， but decreased by about 6 min after adding 1.5% SPH. After adding and 4.5% TSP， the gluten index and the air-holding capacity of the dough increased by 2.22%， but the air-holding capacity decreased after adding 1.5% SPH. Adding 1.5% SPI and 4.5% TSP could increase the contents of SDS soluble glutenin and glutein macropolymer (GMP)， and improve the springiness and moisture content of steamed bread. However， adding 1.5% SPH reduced the contents of SDS soluble glutenin and GMP， and decreased the springiness of steamed bread. Conclusion: by studying the quality of steamed bread， it is found that the quality of steamed bread is the best when the addition of SPI， TSP and SPH is 1.5%， 4.5% and 1.5% respectively. Through the study on the optimum amount of mixed flour of each soy protein， it is found that different kinds of soy protein have different effects on the quality of steamed bread.