Abstract: The paper specifically describes a Feldkamp-type algorithm for the reconstruction of a volume of interest(VOI) from cone-beam(CB) projections. First,we analyze the traits of the reconstruction algorithm,and at the same time,proposes the optimization method by use of symmetry properties in the mode of cone beam scan. Finally,our proposed algorithm is tested using the three-dimensional Shepp–Logan phantom. The experimental results show that the optimization method can efficiently accelerate the speed of image reconstruction and doesn’t affect image quality.