Nondestructive testing technol. has gone through three stages of development, nondestructive inspection, nondestructive testing and nondestructive evaluation. At present, NDT is generally referred to the nondestructive technol. collectively, rather than referring specifically to the second stage mentioned above. Non-destructive testing technol. plays an irreplaceable role in product quality control, and a wide range of applications developed in the manufacturing and inspection of aerospace equipment, as well as applied in the manufacturing and welding of pressure equipment. As one of the "black technol." in aerospace technol., a series of industrial non-destructive flaw detection X-ray films, with cube and T-particle silver halide, produced by Lucky Healthcare Corporation, a subsidiary of China Aerospace Technol. Co. Ltd., has been serving for many years in traditional x-ray detection as same as the several other famous multinational photosensitive materials enterprises. This paper introduces the development of NDT technol., testing methods, and its application in aerospace and railway bridges.