An image positioning method having following steps is provided. The steps include: obtaining world coordinates of two reference points and image coordinates of two projection points corresponding to the two reference points; calculating a plurality of coordinate transformation parameters relative to transformation between any image coordinates and any world coordinates corresponding to a camera according only to the world coordinates of the two reference points, the image coordinates of the two projection points, and world coordinates of the camera; obtaining an second image having an object image corresponding to an object through the camera; and positioning world coordinates of the object according to the coordinate transformation parameters.