Abstract: Polyetheretherketone (PEEK) thermoplastic resin is widely used in aerospace, military equipment, and other fields due to its outstanding properties such as high temperature resistance, high damage tolerance, organic solvent resistance, and fatigue resistance. However, PEEK resin-based composites present challenges including high molding temperature, high resin viscosity, and significant surface inertness. Traditional carbon fiber sizing agents cannot meet the high-temperature requirements of PEEK resin molding, and their poor compatibility with the resin matrix results in insufficient interfacial strength of the composites after molding. Therefore, the development of carbon fiber sizing agents suitable for PEEK thermoplastic resin has become a research hotspot. This paper describes the types of functions, advantages, and disadvantages of carbon fiber sizing agents, and discusses recent research achievements on sizing agents for PEEK resin and their interfacial enhancement mechanisms, and prospects the development trends of sizing agents for PEEK resin, which aims to provide references for the research and development of PEEK resin sizing agents and the preparation of high-performance thermoplastic composites.