The distortion model of the image intensifier in an X-ray angiography system is complicated because it is different for images acquired in different orientations. We proposed a new method for distortion calculation based on grid phantom, and a novel approach for distortion correction. Through analyzing the distortion in several sampled orientations, a correction model is built, which reflects the relationship between the distortion and orientations, and therefore can be used to correct the distortion of images acquired in arbitrary orientations. Experiments are carried out to evaluate the accuracy, which show that the proposed algorithm is effective and efficient for distortion correction of X-ray angiography images and can be used in real-time applications.