In the construction diversion scheme of the Qujiang Fengdongzi navigation project，the flow velocity at the flow section is large during the phase II diversion period. Meanwhile，the anti-scour ability of the downstream river channel is insufficient，and the scour at the head of the upstream cofferdam is significant. In response to these problems，this paper optimizes the construction diversion design scheme on the basis of the physical model test of construction diversion. The paper takes measures of improving the construction diversion plane layout，strengthening the design of the anti-impact facilities of the downstream stilling pool，and optimizing the structural form of the head of the longitudinal cofferdam throughout the year and the length of the longitudinal cofferdam in the dry season，taking into account the general layout of the hub，construction period，construction intensity，project investment，and other factors. It also tests and verifies the optimized construction diversion model and puts forward the diversion design scheme meeting construction requirements for guiding project construction.