To address the dual needs of nutrition and swallowing safety in patients with dysphagia, a novel 3D-printed food system based on a ternary composite material consisting of pea protein (PP), calcium alginate (CA), and whey protein (WP) was developed. Intermolecular forces, infrared spectroscopy, and rheological properties of printed materials produced using different formulations were evaluated. Additionally, the printing accuracy, cooking loss, textural characteristics, and microstructure of the printed samples were characterized. Ionic bonds and hydrophobic interactions within the printed material produced with a 12:1:6 g ratio (PP:CA:WP) synergistically facilitated the formation of a stable 3D protein gel network structure. This, in turn, endowed the printed samples with excellent printing accuracy (80.13%) and shear-thinning properties. Samples with this ratio exhibited a dense microstructure (with pore sizes all less than 200 μm), along with favorable textural characteristics and processing stability. The hardness, viscosity, and chewiness of the printed samples were 262.56, 234.99, and 223.89 g, respectively, with a cooking loss rate of 15.47% after gelatinization. Furthermore, the formulated samples met the Level 5 criteria of the International Dysphagia Diet Standardization Initiative standard, fulfilling the requirements for swallowable food classification. The results confirm that the PP:WP:CA ternary system achieves dual optimization of printing performance and swallowing safety via a proteinpolysaccharide synergistic mechanism. They provide a theoretical foundation for the development of PP-based swallowable foods.