Abstract: Soybean as raw material, the food irradiation technology was used for processing of soybean, the effect of irradiation dose levels and storage time on the number of colonies, crude protein content and functional propertied (nitrogen solubility index , water absorption , oil absorption , emulsification and emulsion stability) of soy protein concentrate were studied. The result indicated that irradiation level of 10kGy could reduce the number of mold in soybean, improve the content of crude protein on dry basis, and improve the functional properties of soy protein concentrate. Compared with the irradiation level of 10kGy , irradiation level of 20kGy could also effectively kill the mold, but it would lead to the reduction of functional properties of soy protein.