Aiming at the modeling of complex terrain and large scale scene of transmission line, this paper discusses the virtual terrain rendering optimization algorithm. On the basis of collecting the terrain elevation data in the location and range of the transmission line, Delaunay triangulation is generated by divideconquer algorithm and pipeline technology. Moreover, a method of optimal parameter selection based on genetic algorithm is introduced to solve the problem of triangular surface with Gauss's surface equation. And the threedimensional visualization of transmission line is achieved on the platform of Qt and OpenGL. Simulation result shows that this algorithm is effective for the virtual visualization of the real terrain of transmission lines.