Abstract: The radar needs to build up homologous database of target characteristic for quickly identifying a target,presently methods of getting target characteristic that actually measure and imitate ,actually measuring method are consume and expensive, can't use in great quantities. But currently imitating method separates computing electromagnetism to imaging,become disadvantage in fast and exact imaging. This text compiles imaging system using MATLAB, which computes a far field using the target that is built up though the FEKO to emulating echo from a backstage with the FEKO, and use the result of calculation to image one dimensional distance imaging and two-dimensional ISAR imaging, thus consumedly raises speed and accuracy of imaging.