In X-ray imaging technology, coded imaging is a process of two steps. The first step is coding process, in which the information of object is collected using coded aperture. The second step is decoded process, in which the coded image is filtered and reconstructed in order to obtain a visible object image with high resolution. There are two kinds of coded aperture, one according to the shape of apertures and the other according to the space position of aperture plane. Wiener filtering is used in the decoded process, because it can obtain better reconstruction results with lower calculated cost. A method of coded imaging using ring-coded aperture and its image restoration technique are presented, the development of coded aperture imaging technologies is described. Difform aperture is adopted in coded and recoded process, compared with each other optimal aperture is chosen. As experiments prove, using this aperture, good imaging result can be gained and restored, because this method combines all of high resolution-capability, large radiation collection efficiency ,and high signal-to-noise ratio.