Abstract: Infrared thermal imaging detection technology, as a non-contact fault diagnosis method, is playing an increasingly important role in the high-voltage electrical industry. This article reviews the current application status and research progress of infrared thermal imaging detection technology in the state monitoring and fault diagnosis of high-voltage electrical equipment. Firstly, it introduces the technical principle and system composition of infrared thermal imaging detection, and elaborately analyzes the specific application cases of this technology in key scenarios such as power transformation equipment, transmission lines, and power plants. Then, it focuses on discussing the research hotspots and innovative achievements in aspects such as infrared image processing algorithms, fault diagnosis methods, and intelligent monitoring systems. Finally, it analyzes the current limitations of the technology and looks forward to future development trends, providing references for researchers in related fields.