Abstract: In this paper, the Xray radiograph technology, which is used for wallthickness measurement of multilayer plastic microsphere, is expounded in detail. The mechanism that Xray is absorbed by the material of plastic shell used as a highgain target in ICF is investigated theoretically. The theoretical analysis and experiment prove that, in vacuum environment, the Xray tube works under 10kV voltage and outputs Xray of 8keV energy, the best image of shell with good contrast and clear interface can be obtained. This technique offers a good measuring method to the shells making．