Abstract: Based on the analysis of traditional FDK filtered-backprojection algorithm for Cone-beam CT reconstruction,two kinds of improvements are presented to accelerate the reconstruction.Together with algorithm improvements,the parallel programming technology Open MP and the SSE,MMX instructions are adopted to optimize the code.The reconstruction from actual cone-beam CT projections shows that these improvements can make the reconstruction much fast while keeping the image quality as good as the traditional FDK algorithm.