1. An image jointing method, comprising steps of: (a) obtaining a first image, a second image and a displacement data, wherein the second image comprises at least a line image; (b) dividing a specific region of the line image as a plurality of image blocks and calculating to obtain a plurality of feature values, wherein each of the feature values is corresponded to each of the image blocks; (c) comparing the feature values and utilizing an initial coordinate of the image block corresponding to the maximum of the feature values as a feature point representing the line image; (d) corresponding the feature point to a base point of the first image according to the displacement data and obtaining a first jointing point corresponding to the first image and a second jointing point corresponding to the second image according to the base point and the feature point; and (e) jointing the first image and the second image through the first jointing point and the second jointing point.