Abstract The binding of proteins and polysaccharides/polyphenols can modify the interfacial properties of proteins. Therefore, this study aimed to explore the feasibility of soy protein‐glucan‐coumarin complex (S‐G‐C) fabricated by subcritical water treatment as novel emulsifiers with decent physicochemical stability. The addition of β‐glucan and coumarin (CM) led to partial unfolding of soy proteins, the corresponding particles decreased and structure became tighter, and thereby the ternary complexes, which were formed mainly through hydrogen bonding and hydrophobic interaction exhibited more suitable three‐phase contact angles (92.6°) compared with soy protein alone and binary complexes. CM might increase hydrophobic effect while β‐glucan attached to the outer layer might provide steric repulsion, which effectively improve physical stability of Pickering emulsion against environmental stresses and retard droplet aggregation and creaming during the 28 days storage. This study provides a reference for the preparation of novel emulsifier with improved physicochemical and functional performance.