SAR imaging systems are as a complement to passive remote sensing but the process of image formation in this systems is so complex So that the final image in the system is formed after the three basic steps: raw data acquisition, forming the signal space and image space. In addition, various factors within the system and outside the system are involved in the information that recorded by SAR, such as radar, platform, processing algorithm, imaging region and channel that each of them have many sub-parameters and this adds the complexity of the behavior of SAR. So due to the complexity, providing the model that describes how the SAR imaging system is highly important. In this paper, at first, the performance of the SAR image formation in spotlight mode placed on analytical modeling and after that the model comes in a soft implement. The implement includes three basic steps of image formation. So that raw data acquisition is done in CST and the signal and image formation are done in MATLAB software. This implementation provides a lot of abilities. So you can simulate the effect of the affect parameters in SAR images and better interpretation of themes. Also, the validity of the proposed solutions in electronic warfare or passive defense for SAR imaging systems can be studied by it.