High pressure homogenization is one of the most common physical modification methods in protein processing. However, the pressure of homogenization generally does not exceed 40MPa in actual production due to the limitation of equipment. Therefore, it is of great importance to study the effect of low pressure homogenization (0~40MPa) on the solubility and structure of soybean protein isolate. The effects of lowpressure homogenization (0~40MPa) on the solubility and structure of soybean protein isolate (SPI) were studied by measuring particle size distribution, solubility, emulsification, tertiary structure and thermal stability. The results showed that lowpressure homogenization treatment could reduce the particle size of SPI, significantly improve the solubility, and the solubility was positively correlated with emulsifying ability and emulsifying stability. The linear fitting model functions were obtained, and the correlation coefficients were 0.9568 and 0.9625, respectively. Fluorescence spectrum analysis showed that the structure of SPI was expanded with the increase of homogeneous pressure, the maximum absorption wavelength was redshifted, the internal tryptophan group was exposed, and the fluorescence intensity was increased with the increase of homogeneous pressure. At 30MPa, the fluorescence intensity was the highest. When homogeneous pressure was further increased, the protein molecules were aggregated, and the former exposed active groups were hided in the inside of SPI with a slight decrease in fluorescence intensity due to inward crimping of active groups. The above results were verified by the analysis results of thermal stability.