An X-ray imaging apparatus may include an image acquirer configured to acquire a plurality of X-ray images of an object in different energy bands; and an image processor configured to perform scattering correction on the plurality of X-ray images to remove X-ray scattering from the plurality of X-ray images, perform material separation on the plurality of X-ray images on which the scattering correction has been performed to acquire material information of at least one material included in the object, and repeatedly perform the scattering correction and the material separation depending on whether a predetermined condition is satisfied.