Disclosed herein are an X-ray detection panel, an X-ray image generating module, an X-ray imaging apparatus, and a method of generating an X-ray image. The X-ray imaging apparatus includes an X-ray generator configured to emit X-rays; an X-ray detection panel comprising a plurality of pixel groups, each pixel group configured to detect X-rays having an energy band and to convert the detected X-rays into electrical signals; and an image processor configured to acquire readout data from the electrical signals of at least one of the plurality of pixel groups, to calculate estimated data, and to generate an X-ray image by combining the readout data and the estimated data.