It is important to consider the effect of the navigable flow condition when a newly ship lock is built beside the existing ship lock.An unreasonable layout of ship locks may lead to safety problems during operation.We carry out a physical model test with the scale of 1??100 to study the navigable flow conditions of the upstream entrance area and berthing section before and after the construction of Wan'an second ship lock，and propose the optimized layout scheme of the entrance area of the approach channel based on the test results and terrain conditions.The results show that the flow conditions of the second ship lock near the entrance and piers in original design scheme exceed the standard，and the flow conditions of the first ship lock are worse than the situation before the second ship lock is built.The flow conditions of upstream at second ship lock in all conditions of optimized scheme meet the requirements，and the flow conditions of the first ship lock are better than that before the second ship lock is built.