Aiming at the practical problem that the 1.6 m draught control standard of Silin and Shatuo ship lifts in Wujiang River leads to the low loading capacity of the ship，we conduct systematical prototype tests of the over-draught ship to enter and leave the chamber to demonstrate the feasibility of upgrading the draught standards for ships. The results show that the ship leaving the chamber is the control condition，the maximum sinkage of the ship with the draught of 2.0 m is measured as 16.46 cm，and the under-keel clearance is more than 30 cm. An improved prediction formula based on the actual ship’s test data can increase the prediction accuracy of the ship’s sinkage by more than double. According to the current water level coordination mechanism of the two ship lifts，the upstream and downstream water levels change within 10 cm，and the maximum draught of the ship could be increased to 2.0 m. It is recommended that the draught control standards could be carried out from 1.8 m to 2.0 m during the navigation trial period.