Annular artifact eliminating method and X-ray CT apparatus

The invention provides an annular artifact eliminating method and X-ray CT apparatus, which is aimed at transforming the orthogonal coordinates of each pixels of the X-ray CT apparatus' reconstructed images into the coordinates of the polar coordinate system using equal-central dot as the original point, based on the polar coordinates, each pixel can be configured into the polar coordinate system and made into intermediate image, artifacts-eliminating treatment parallel to theta axis can be carried out to the intermediate image, then the polar coordinates of each pixel of the processed intermediate image is transformed into the coordinate in rectangular coordinate system.