The low rehydration properties of commercial soy protein powder (SPI), a major plant−based food ingredient, have limited the development of plant−based foods. The present study proposes a treatment of soy lecithin modification combined with Alcalase hydrolysis to improve the re- hydration of soy protein powder, as well as other processing properties (emulsification, viscos- ity). The results show that the soy protein–soy lecithin complex powder, which is hydrolyzed for 30 min (SPH–SL−30), has the smallest particle size, the smallest zeta potential, the highest surface hydrophobicity, and a uniform microstructure. In addition, the value of the ratio of the α−helical structure/β−folded structure was the smallest in the SPH–SL−30. After measuring the rehydra- tion properties, emulsification properties, and viscosity, it was found that the SPH–SL−30 has the shortest wetting time of 3.04 min, the shortest dispersion time of 12.29 s, the highest solubility of 93.17%, the highest emulsifying activity of 32.42 m2/g, the highest emulsifying stability of 98.33 min, and the lowest viscosity of 0.98 pa.s. This indicates that the treatment of soy lecithin modification combined with Alcalase hydrolysis destroys the structure of soy protein, changes its physicochemical properties, and improves its functional properties. In this study, soy protein was modified by the treatment of soy lecithin modification combined with Alcalase hydrolysis to improve the processing characteristics of soy protein powders and to provide a theoretical basis for its high−value utilization in the plant−based food field. Keywords: soy protein powder; soy lecithin; enzymatic hydrolysis; rehydration property; emulsifying property