Composite structures are important for aero-engine, the wings and main body of aircraft, wind turbine, these components play an important role in aviation, mechanical and civil engineering. However, the safety of composite structures are affected by the complexity and defect in manufactures, which is always the bottleneck of composite material application. Thus, the damage detection and health monitoring become the hot topic in a lot of regions. Based on the demonstration of the development and applications, the key technologies of the title issue are discussed and concluded.