Additive manufacturing (AM) is an important technology in Industry 4.0. In recent years, solid-state-based additive friction stir deposition (AFSD) has attracted much attention, as it can avoid the inherent defect of melting and rapid solidification in electron beam-based or laser-based AM technologies. The macro and micro laws, finite element simulation, and engineering application technology of the AFSD process are still in their early stages. This paper mainly reviews the equipment, mechanism, the effect of process parameters on macro/micro characters, and the engineering applications of the AFSD process. Further, based on the complex loading conditions during the AFSD process, some perspectives are proposed, including the characterization method, unified constitutive model, novel composite manufacturing technology, and systematic study of the AFSD process.