Qingfeng hub is located in the middle reaches of the Cao’e River. In order to meet the needs of upstream water transportation，it is necessary to rebuild the existing Qingfeng hub and build a new ship lock. The discharge direction of the sluice gate of the hub is oblique to the downstream approach channel of the new ship lock，which makes the downstream flow conditions of the ship lock more complex and the navigation conditions relatively poor. In order to ensure the normal navigation of the downstream approach channel of the ship lock，a plane two-dimensional mathematical model of the middle reaches of the Cao’e River is established and calculated，and its improvement effect on the navigation flow conditions is studied by arranging different diversion walls. The results show：1）The training wall parallel to downstream approach channel can better improve the flow conditions in the channel，and the improvement effect is 70%~90%. 2）Extending the length of the training wall can further improve the navigable flow conditions of the approach channel，and the improvement effect can reach 100%. 3）By diversion pier，the improvement of longitudinal velocity is more effective than that of transverse velocity，and the improvement effect of longitudinal velocity is 100%，while the improvement effect of transverse velocity is less than 2%.