In this study we used pepsin to hydrolyze the soybean protein isolates,and obtained a series of hydrolysate.We also studied the solubility and the effects of different store conditions,such as normal temperature storage,ice storage and freeze storage on the emulsifying capacity of SPI.As a result,solubility can be enhanced by pepsin hydrolysis,and 5h is the best time frame.Moreover,emulsifying capacity can also be enhanced,at normal temperature the droplet size distribution showed a upward trend at first and then showed a downward trend with the time extension.The ability of anti-Freeze and Thaw is better as the time extended.