Abstract：Since Wireframe does not have the face information, the hidden line of its projection drawing cannot be removed by the existing methods. In this paper, an efficient algorithm for removing the hidden line from wireframe projection drawing was presented. In projection drawing, the intersection of the two lines was identified by bounding box and directed triangle. Further, the visibility of intersection lines could be determined by projection model. The occlusion matrix made up for the lost depth information during projection. The connected matrix of topological relationships between vertices was renewed by occlusion matrix, and the projection drawing defined by connected matrix had no hidden line. The test results show the high efficiency and stability of the proposed algorithm.