With the increasing demand for sustainable foods among consumers, plant-based meat, as an alternative to traditional meat, has received increasing attention. High-moisture extrusion is one of the crucial steps in the preparation of plant-based meat, which utilizes the synergistic effects of high temperature, high pressure, and high shear to mimic the fibrous structure and texture of meat. However, this process leads to complex physical and chemical changes in proteins and auxiliary materials, resulting in significant differences between the product and traditional meat in terms of color, texture, and flavor. Therefore, the addition of exogenous additives has become a key research area for improving product quality. This paper reviews the effects of different additives (such as proteins, lipids, polysaccharides, crosslinking agents, and other additives) on the structure and quality of plant-based meat during high-moisture extrusion, explores the mechanisms of protein-protein, lipid-protein, polysaccharide-protein, and crosslinking agent-protein interactions, and analyzes their enhancing effects on the texture, flavor, and nutritional value of plant-based meat. This paper aims to provide a theoretical basis and technical support for further research and development of plant-based meat products.