In this paper， a series of composite peanut protein isolate (PNPI) powders were prepared by co-spray drying with maltodextrin， trehalose， polyglycerol fatty acid esters， and sucrose fatty acid esters as co-spray drying agents， to investigate their effects on the physicochemical and emulsification properties of PNPI. Results demonstrated that the addition of maltodextrin and trehalose reduced the particle size of PNPI from 654.10 nm to 356.21 nm and 550.65 nm， respectively. All four co-spray drying agents increased the hydrophobicity of PNPI by 1.18-1.46 times. Compared to other agents， maltodextrin significantly enhanced the emulsification performance of PNPI powders， with emulsification activity index (EAI) and emulsion stability index (ESI) being 1.21 and 1.69 times higher than those of pure PNPI powder， respectively. Furthermore， all composited PNPI powders with co-spray drying agents effectively stabilized both 25% and 75% oil-phase Pickering emulsions. All emulsions exhibited shear-thinning behavior with increasing shear rates. Confocal laser scanning microscopy confirmed oil-in-water emulsion structures for all emulsions， with maltodextrin-composite PNPI powder producing the smallest emulsion droplets (below 70 μm) and the highest viscosity. Conclusion: Co-spray drying agents can improve the physicochemical properties and emulsification characteristics of PNPI powders， with maltodextrin demonstrating the most pronounced enhancement， showing promising potential for PNPI applications in the food industry.