The Chaohu Ship Lock Hub is located at the entrance from Chaohu River to the Yuxi River,and is a key control project for the Heyu line channel and Chaohu River flood control.Its upstream is adjacent to the Chaohu ecological scenic area.Due to the constraints of ecological and flood prevention factors,construction conditions are restricted.The current technical condition of the first-line ship lock is poor and cannot operate normally.The throughput capacity of ship lock cannot meet the demand for transportation volume.Based on the width of the old lock chamber and the analysis of the proportion of ships passing through the lock chamber with different widths,it is proposed that the ships passing through the lock chamber should choose the ship lock with better adaptability to the size of the lock chamber according to the width of the ship,and try to improve the utilization rate of the lock chamber as much as possible.After the renovation of the first-line ship lock,the minimum water depth of the threshold is 4.5 m.Through the analysis of the critical speed of the ships passing through the lock,it is found that under normal entry and exit speed conditions,the maximum draft of the designed ship when fully loaded can be increased from the allowable value of 2.80 m to 2.92 m.The proportion of 2,000-ton class ships that meet the requirements for passing through the lock can be increased from 64.68% to 83.10%.When the speed is reduced to 0.6 m/s,it can basically meet the requirements for all designed 2,000-ton class ships to pass through the lock.At the same time,from the perspective of transportation economy,the rationality of the maximum draft value of the designed ship is demonstrated by analyzing the matching between the threshold water depth of the ship lock and the downstream channel design water depth through the design of the ship type.