After long-term service in rugged environment,polypropylene pipeline easily forms defects such as corrosion on the wall,deposition and crack. The defects greatly reduce the performance of the pipeline and easily cause accidents. The rigorous non-destructive inspection to the polypropylene pipeline must be carried. Infrared thermal wave non-destructive inspection technology was applied to detect three kinds of flaws which were embedded in polypropylene pipeline. Data which was collected by IR camera was processed,the typical time thermograph and the curve of logarithmic temperature-time can be extracted. Via to analyzing the time-variation gray scale of typical time thermograph and the slope coefficient of curve,the type and the information of position of flaws can be obtained. Utilizing the software of image processing,the area of corrosion can be calculated. The results indicated that this technology can make fast,direct-viewing,effective examination for the polypropylene pipeline with 3 kinds of common flaws.