Abstract: A nonuniform back-projection reconstruction method for computerized tomography is presented. In the uniform back-projection reconstruction method the projection difference-between a measured ray sum and a computed ray sum is uniformly distributed to the cells in the ray, but in the nonuniform back-projection reconstruction method the projection difference is nonuniformly distributed to the cells based on the weighted grey coefficient of the cell. A qualitative improvement of reconstructed images by the new reconstruction method is evident, especially in the incomplete projection cases.