Abstract: Binders are the core component of metal injection molding (MIM), and the binder modification is an important approach to improve the comprehensive properties of feedstocks, green parts, and sintered components. The research progress of modified binders for metal injection molding was reviewed in this paper, and the modification strategies were summarized, including physical modification, chemical modification, and powder surface-treatment synergistic modification. The internal modification mechanisms were analyzed from interfacial interaction, rheological property regulation, and debinding-sintering stability. In the results, the hydrogen bonds and covalent bonds serve as the major chemical forces to strengthen powder-binder interfacial bonding. For the plastic-based, wax-based, and mixed binder systems, adjusting molecular chain entanglement and compounding polymers with viscosity gradients should be adopted to optimize the pseudoplastic flow behavior. The rational component design of binders can regulate the pore evolution during debinding, reduce the residual-carbon defects, and realize the coordinated matching between debinding and sintering processes. Modified binders can increase the green density and distribution uniformity, improve the shape retention of green bodies, mitigate the carbon residue in sintered parts, and raise the relative sintered density to more than 95%～99% of theoretical density. It is concluded that the binder modification provides the technical support for large-scale fabrication of high-precision powder-metallurgy components and promotes the green development of metal injection molding technology.