The inevitable occurrence and development of defects in industrial and engineering materials in the service process,effectively identify of early microdefects,can advance the level of disaster disposal to the embryonic stage of hazards,and fundamentally improve risk controlling capabilities.The energy of vibrating solid is irreversibly dissipated to heat due to the internal friction law and the loss energy includes ultrasonic attenuation.Internal friction is sensitive to the structural form and can sensitively react to defective structures in solids.Therefore,the idea of analyzing the temperature field of the measured object and interpreting the structural characteristics of identified microdefects based on the ultrasound excitation thermography has gradually attracted research interest.The effective realization of ultrasonic selective thermal excitation at microdefects has become the focus of research.The origin and the detection principle of the ultrasound excitation thermography are summarized.Focusing on the detectivity of microdefect,the research status of this technology is systematically elaborated from four aspects:application material,defect resolution scale,sound vibration heating mechanism of microdefect and ultrasound thermal excitation efficiency.On this basis,the further research direction is summarized to realize the large scale efficient detection and accurate interpretation of microdefects.