Additive manufacturing technology, known for its advantages in rapid layer-by-layer 3D printing, personalized production, and flexible manufacturing, has gained widespread applications in the manufacturing industry. This paper provides an analysis and summary of the recent progress in lightweight metal solid-state additive manufacturing technology and its related process mechanisms. The primary solid-state additive manufacturing technologies currently include ultrasonic additive manufacturing, cold spray additive manufacturing, and friction-based additive manufacturing. The research and application status of solid-state additive manufacturing technology for lightweight metal materials are particularly emphasized, and the characteristics of these three types of solid-state additive manufacturing technologies are compared. In the end, the paper highlights the key directions for future research in solid-state additive manufacturing technology, including additive process mechanisms, simulation study of multi-physics and multi-scale, application of various materials, external field-assisted process modification and optimization through artificial intelligence.