In order to solve the problems of lacking depth information of single vision and low real-time of binocular vision in transmission line monitoring, this paper proposes an optimized scheme based on binocular vision measurement. This scheme moves the massive calculation in traditional binocular vision measurement process from monitoring stage to preparation and builds a stereo space model of transmission line. The details of the method are described, its feasibility and validity are examined by experiment via Matlab. A stereo space monitoring database is built in the experiment after wire coordinates 3D reconstruction, space function fitting, and protected area calculation. At last, the invasion of a measured object is estimated by database retrieval. The result shows that the space location of the measured object is belong to the monitoring area. Therefore, the proposed method is effective in transmission line space modeling and measurement. This work is supported by Key Scientific Research Program of State Grid Hubei Electric Power Company (No. 52153216001C).