A derivation Hilbert backprojection (DHB) reconstruction algorithm based on the filtered backprojection (FBP) algorithm in equispaced fan-beam CT is proposed and realized. Because of the improvement of sharp cut-off characteristic of DHB filtering function in high frequency, the experimental result shows that the reconstructed image using DHB is smoother than that using FBP. Simultaneously, the distance weighting in backprojection operator is got rid of, which leads to the reduction in reconstruction time.