To design a more reasonable layout scheme of ship lock，we carry out the experimental research on the navigation safety of the original design scheme and the modified scheme of the first ship lock of the Jinweizhou hub expansion project in Xiangjiang River.Based on the hydraulic model test，we apply the small-scale ship model technology to observe and analyze navigation parameters，such as rudder angle and speed. The results show that the modified scheme layout is more reasonable than the original design scheme layout，and the navigable flow conditions are optimized. When Q≤5，210 m3/s，the navigation parameters of the upstream and downstream channel of the first ship lock do not exceed the corresponding limits，which can generally meet the navigation requirements of 1，000 t self-propelled vessel （still water speed：18 km/h）. From the comprehensive analysis of the study results，we suggest that the maximum restricted navigable flow of the first ship lock should be 5，210 m3/s.