Abstract: By calculating the recovery distance of water flow, it can be known whether the navigable flow condition in the downstream approach entrance area is affected by the upstream power station under different discharge conditions, which can provide a reference for the dispatching operation of the power station. Taking Jinghong Hydropower Station as the research background, we analyse the flow distributions along the river under three conditions: power generation, controlled discharge power generation and open-discharge shutdown, and those are compared with the flow distribution under the condition of full sectional discharge without dam. The concept of flow recovery distance is put forward, and the flow recovery distances under different conditions are calculated. The results show that the recovery distance of both sides is larger than that of the middle section. The larger the proportion of discharge width, the shorter the recovery distance; and the larger the discharge, the longer the recovery distance. By comparing the flow conditions in the approach entrance area under the full sectional discharge and the limit discharge condition, it can be seen that when the water recovery distance is greater than the length of the approach channel, the flow conditions in the approach entrance area will obviously change under the corresponding discharge condition, then the influence of the discharge from the power station on the downstream navigation should be considered.