Abstract: The paper accelerates cone-beam back projection computation by improving GPU technique of render-to-texture,and enhances performance of Katsevich-type CT reconstruction algorithm for single circular arc trajectory.The projection data are filtered on CPU,and then rearranged and downloaded to the graphics hardware as the RGBA four-channel textures.Two floating output textures are bound to different attachment points of a frame buffer object,which enables the rendering results to be written to the textures and added with the previous back projection data.Rectangle grids are coded as quadtree structure applied to speed up rendering of object slices.Experimental results show that under the condition of big cone angle the proposed method can obtain high quality reconstructed images in near real-time reconstruction speed.