Abstract: Mobile high-energy X-ray radiography system(MRG), which is a truck-carried miniaturized 9MeV electron linear accelerator, can move to solid rocket motors’ storeroom. This makes it possible to do on the spot nondestructive testing for these large objects. The storerooms have almost no any radiation protection measures, so large distance from the source, geometric advantages or man-made protection walls are used to attenuate the high energy X-ray. Process and quality control principles have been made to ensure the coherence and quality of NDT in different places. A large number of grain voids, interfacial debonding, inclusions and other defects have been detected by this system after running several years. The NDT results have played important roles in judging the quality of SRM and guiding the SRM design and production.