Disclosed herein are an X-ray imaging apparatus for forming an X-ray image having reduced noise by correcting errors according to characteristics of each of a plurality of pixels and a control method therefor. The X-ray imaging apparatus includes an X-ray generator to generate X-rays and irradiate the generated X-rays, an X-ray detector to detect the irradiated X-rays and output X-ray data by counting the number of photons having an energy that is equal to or greater than threshold energy among photons contained in the detected X-rays, for each of a plurality of pixels a function acquisition unit to acquire calibration functions for the respective pixels using X-ray data output for a plurality of predesigned phantoms, and an image correction unit to correct an X-ray image of an object on a per pixel basis using the acquired calibration functions.
