Abstract: In order to improve the functional properties of pea protein isolate (PPI), such as solubility, emulsification, foaming capacity, and broaden its application the food industry, in this study, PPI was selectively extracted using ammonium sulfate precipitation, and was covalently grafted with chitosan oligosaccharides (COS), carrageenan oligosaccharides (CAS), alginate oligosaccharides (AOS), and agaric oligosaccharides (AGS) at an oligosaccharide-to-protein ratio of 20% using cold plasma (CP) induction. The effects of this non-thermal covalent grafting with marine oligosaccharides on the solubility, thermal stability, foaming capacity, and emulsifying properties of PPI were investigated. The results showed that CP treatment induced effective and rapid covalent grafting between PPI and marine oligosaccharides. The highest grafting rate (17.89%) was observed in the PPI-COS combination. In terms of mixtures, the solubility of the covalent complexes was significantly improved after CP induction relative to those without CP treatment, in the order of AGS/PPI-CP>COS/PPI-CP>CAS/PPI-CP>AOS/PPI-CP. Among them, AGS/PPI-CP showed the highest solubility (0.775 mg/mL), while COS/PPI-CP exhibited the greatest foaming capacity (146.67%), emulsifying activity (123.21%), and emulsion stability (37.73%). These enhancements significantly improved the interfacial adsorption of PPI, contributing to greater stability at both air-water and oil-water interfaces. In conclusion, non-thermal covalent grafting of marine oligosaccharides with CP was effective in enhancing the functional properties of PPI. These findings provide valuable guidance for the development of functional pea protein-based food products and related applications.