Linhuan ship lock is located in the south of Linhuan control lock，about 30.0 km away from Likouji，the provincial boundary，and 31.5 km away from Nanping lock.The connecting section of the downstream approach channel is located in the turning river section，with a turning angle of about 75°.Affected by the terrain，the main stream of the river flows into the downstream main channel close to the convex nozzle on the right bank，resulting in counterclockwise reflux between the connecting section of the approach channel and the concave bank.This exerts a compressive effect on the approach channel flow，with significantly narrowed width of the local mainstream.The physical model test shows that the mainstream of the river forms an obvious shear to the flow in the entrance area of the approach channel，resulting in a large reflux range in the entrance area with a length of nearly 350 m.As a result，multiple complex reverse reflux combined flow patterns are formed，and the flow conditions are very complex.Therefore，corresponding engineering measures should be put forward for improvement.By dredging the channel and increasing the separation submerged dike，we solve the poor flow pattern in the downstream approach channel，large cross-flow velocity exceeding the standard，large reflux intensity in the entrance area，and inability to meet the specification requirements.