During the construction period of the Longxikou Navigation-power Junction project,navigation interruption is not allowed,with compact junction layout,large flood flow,and heavy flood control tasks.Additionally,the construction flow diversion adopts the phased cofferdam diversion,which is divided into three phases.According to the on-site progress,the power plant and ship lock will be constructed spontaneously in the first flood season of phase II,and the optimization design of flow diversion and flood control is particularly important for the project construction.Earth-rock cofferdam of ship lock is added in the first flood season of phase II,and flow diversion procedures of subsequent construction are optimized.The physical model and mathematical model verify that optimization design is feasible.The leading group uniformly directs flood control and formulates comprehensive flood control measures,ensuring the flood control safety of the construction project.