1. A method of rapidly establishing an image spatial relation using planar filtering limitation, comprising the steps of: getting a plurality of continuous image data at different shooting angles such that each image data contains a plurality of feature points; randomly selecting a preset number of feature points from the image data for performing a comparison; determining if the selected feature points are coplanar; when the selected feature points are non-coplanar, then the selected feature points are used to perform an epipolar geometry fundamental matrix computation; and when the selected feature points are coplanar, then a median error value obtained in the current computation is directly set as a maximum value.