Abstract: Owing to the complex curved surface structure of aeroengine blades, it is difficult to detect tiny cracks formed during servicing. In this study, ultrasonic infrared thermography technology was used to detect the blade cracks of an aero engine. Ultrasonic infrared thermal imaging technology was studied, and an experimental platform for ultrasonic infrared thermal imaging was built. In addition, the working blade of an aero engine with cracks arising from actual servicing was detected. The results of ultrasonic infrared thermography were compared with those of osmotic detection and metallographic detection. Experimental results show that in the working blade of the aero engine, ultrasonic infrared thermography technology detected two crack defects and one opening defect, whereas only one crack defect is detected by penetrant testing and two crack defects are detected by a metallographic microscope.The widths are approximately 15 μm and 0.5 μm, respectively, which are consistent with the detection results of ultrasonic infrared thermography. The results show that ultrasonic infrared thermography technology can effectively detect crack defects in aeroengine blades with complex curved surfaces.