The structure of the vertical multijunction detector is introduced, and the result and technologcial conditions of preparing junction by thermomigration method are presented. In addition, the insulation line method of processing electrode wire is specially introduced; the problem of photoetching electrode after thermomigration is solved; the effects of technologcial conditions on device performance are analyzed. Besides, the difficulty in connecting all P regions is solved, and the aim of zero shade for sensitive regions is achieved. Specially, in order to realize integrating multicell device, a method of widening the size of electrode wire is described. Several important parameters are described, and the math model for the relationship of the X-ray intensity with both photovoltage and photocurrent is set up. At the same time, we introduce the measurement relation between the output voltage of the device and X-ray intensity, which shows that the measurement data and theoretical results are consistent. Finally, we analyze the measurement data, and demonstrate that the device has good enough sensibility and resolution.