Disclosed herein are an X-ray imaging apparatus and a method for controlling the same. The X-ray imaging apparatus includes an X-ray generator configured to radiate first-energy X-rays toward an object, an X-ray detector configured to detect the first-energy X-rays which propagate through the object, an image processor configured to generate a first object image which correspond to the detected first-energy X-rays and to estimate a second object image which corresponds to second-energy X-rays based on the generated first object image, and a controller configured to control the image processor to repeatedly estimate the second object image by controlling the X-ray generator to repeatedly radiate the first-energy X-rays toward the object.