In additive manufacturing processes, parts processed by electron beam or laser powder melting technology have defects such as melting and solidification. The Additive Friction Stir Deposition (AFSD), a solid-state additive manufacturing technology, overcomes these defects and has been applied. The deposition process does not involve material melting and solidification, resulting in high material density, small grains, and a uniform, equiaxed, and fine microstructure in the deposited components, with good toughness and mechanical properties reaching the level of forging. Although there have been some studies on AFSD for materials such as aluminum alloys, magnesium alloys, and titanium alloys, the process is still in its early stages. Therefore, this article reviews the research and application of the AFSD process over the past 20 years. It elaborates on principles, equipment, processes, properties, applications, and development trends, providing a reference for AFSD research.