Abstract: In order to improve the solubility of rice protein in aqueous solutions by using oat protein-coupled co-assemble hybridization technology, in this study, different ratios of rice protein and oat protein were used as raw materials, and the two proteins were mixed at pH12, and then restored to neutrality for the co-assemble hybridization. The solubility of the protein was determined and the mechanism of action was explored by analyzing sodium dodecyl sulfate-polyacrylamide gel electrophoresis, particle size, microscopic morphology, emulsification characteristics, foaming characteristics, and Fourier transform infrared spectrometer. The results indicated that the solubility of rice protein-oat protein was higher than that of rice protein (8.49%±1.53%), and the highest solubility 93.07%±2.15% was achieved at the ratio of 1:0.6 (rice protein/oat protein). The particle size of the rice protein-oat protein after co-assemble hybridization was about 0.1 μm, while the structure became looser and hydrophobic interaction and hydrogen bond between rice protein and oat protein were changed, which increased the solubility of rice protein and further improved the emulsification and foaming characteristics. In conclusion, the oat protein-coupled co-assemble hybridization technology is a robust method that can solve the poor water solubility of rice protein.