Objective: So far, CT back projection technology is already quite mature, this article is a basic research for CT back projection technology, which uses software method to realize back-projection technology, so that you can have a better under-standing of CT back-projection technology. It uses computer soflware programming to realize computer simulation of CT back-projection reconstruction: algorithm is CT back projection algorithm. While realizing back-projection reconstruction, we can choose a suitable faltering function to process received image data in finquency domain, so as to achieve the purpose of the elimination of simple back-projection arising from star-shaped artifact. Methods: The programming environment uses VC soft-ware platform integrated development environment ODE). It bases on the CT filtering back-projection reconstruction algorithm and develops a PC software of graphic user interface. By choosing the value of the various parameters related to the back-pro-jection, we can obtain different effect of back-projection reconstruction image, so that we can compare the result of different pa-rameters to get important factors which effects CT filter back-projection most. Results: We realize the simulation of image re-construction of standard phantom. The interface is easy, so makes it very convenient for deeper understanding of back-projec-tion reconstruction, at the same time the filtering function based on the frequency domain also partly eliminates the star artifact caused by reconstruction process. The reconstruction image of the standard phantom achieves the desired effect. Conclusions: The software simulation of the back-projectiun reconstruction can show the process of recoustruction clearly. By change the val-ue of the parameters, we can have a better understanding of the reconstruction algorithm, so that we can find more suitable fil-tering function.