Abstract: This paper provided an overview of the basic principles of CT imaging algorithms. Based on computer simulation experiments, it investigated the effects of Ramp and Shepp-Logan filters on imaging quality. Given that the Ramp filter had excessive high-frequency gain and the Shepp-Logan filter suppressed high-frequency gain too much, resulting in a small edge preservation index, this paper proposed a modification to the Shepp-Logan filter. The newly modified filter performed better than the Shepp-Logan filter in all aspects of evaluation criteria. Additionally, the paper explored the correlation between the number of scan projections and the generation of artifacts. In the analysis of the integral formula for angle integration of filtered projection data, it was found that the pixel value was the line integral along the diameter of a circle with the Cartesian coordinate system of the filtered projection data at pixel coordinates (x,y) and the origin point (0,0).