The method of comprehensive strengthening with external pre stressed force and pre stressed carbon fiber board and its superiority have been expounded in this article. By applying the comprehensive strengthening method in Chongqing Gaoliang interchange overpass, comparing the theoretical deformation increment and stress increment of the reinforced control sections with the measured values, the result shows the anticipated target has been achieved. Finally, it gives the flexural bearing capacity calculation formula of comprehensive reinforced beams with rectangular section, T shaped section and I shaped section under ultimate state.