Regarding the complicated and harsh navigable flow conditions at the approaching entrance region downstream of a navigation power hub，we compare and analyze the water flow conditions of the approaching entrance region under different separation levee arrangement schemes relying on an experimental study of a navigational power project. The results indicate that the separation levee can change the flow directions of the downstream flow in the main channel，and reduce the squeezing and friction by the mainstream on the water flow in the approaching entrance region. Compared with the scheme without the air-permeable separation levee，the installation of the air-permeable separation levee can reduce the cross flow and backflow caused by the main flow of the leakage at the bend. After increasing the length of the permeable separation levee，the direction of the flow velocity on the surface of the main flow can be changed to improve the navigable flow conditions of the downstream approaching entrance region on the curve. Furthermore，the reasonable application of the separation levee effectively reduces the lateral and reverse velocity caused by the main flow.