Abstract: The infrared thermography (IR-Thermography) inspecting system based on a flash thermography(FT) was applied to the nondestructive testing of a set of composite reference blocks with artificial flaws. As the results showed, the IR-Thermography NDT method is able to provide with a dependable result for the detection of delaminations with stipulated size and depth in laminates, debonds and core crush in honeycomb core sandwich, respectively. Meanwhile, it is proved that the inspection sensitivity and capability is greatly dependant on the depth of defects. Selecting an applicable pumping frequency and time is necessary to acquire a dependable thermal image in practical inspection. It is finally concluded that the IR-Thermography is a high-performance in-situ NDT method of Airplane composite panels.