Abstract: Defect detection and elimination inside the wall of metal pipeline is very important for efficient transportation. The ultrasonic infrared thermal wave nondestructive test technology was employed to detect defects in metal pipeline. It adopted ultrasonic as a heat source to excite the sample and a high frequency infrared camera as a detector to capture the surface temperature, which combined the advantages of ultrasonic heating and infrared thermal technology. The pipeline with wall thickness of 3.33mm was inspected by this technology. By analyzing the temperature signal and typical time thermograph, the effective flaw information was obtained. Experiment conclusively indicates that the position of the defects on the inner wall can be accurately detected by the ultrasonic infrared nondestructive test technology.