Beeline and ellipse are the important elements in computer vision measurement. A spatial moment operator with three gray model is proposed. Firstly, the edge at the level of pixel is located by the Laplacian of gaussian operator, and subpixel location of the edge is obtained by the spatial moment. Then, the beeline and ellipse edge pixel pionts are extracted by the Hough transform at the level of subpixel. Finally, the subpixel beeline and ellipse edge is extracted by the least square curve fitting method. The experimental results show that spatial moment subpixel edge location and the extraction of beeline and ellipse on image plane possess high precision and high stability.