The traditional bridge construction risk evaluation method has defects in user-friendliness and systematicness, and ignores dynamic traffic risks. This paper is based on the research conducted on the newly built G72 Separation Bridge of Chang-Qi Expressway, in which the traditional LEC Method is improved by quantifying the construction risk index and traffic risk index, and the risk of this bridge is evaluated comprehensively by the use of WBS-RBS and AHP. The results show that the bridge can be divided into 4 sub projects and 18 unit operations, and 17 risk indicators are identified in accordance with the HSE risk management model; 192 risk sources are determined by coupling operation index and risk index, among which 14 are above level ; Through the analytic hierarchy process, 7 unit Ⅲ operations and 1 sub-divisional project with risks above level are obtained, and the total risk of the Ⅲ bridge is 171.8, which is also a level risk. Finally, construction risk management and control Ⅲ measures are proposed from the aspects of traffic organization and safety protection, which provides theoretical and practical guidance for similar projects.