A junction lock is the main control project for the navigation engineering of the involved reach，and its construction plays an important role in the channelization of the river. Due to the large scale of the lock chamber，the high working head，and the high water delivery energy，solving hydraulic problems in water delivery is the key link of lock design. To ensure that the ships and locks meet relevant requirements in water delivery，we probe into the hydraulic characteristics，berthing conditions，and flow conditions of approach channels during water delivery on the basis of tests by a physical model with a scale of 1:30. The results show that under the recommended arrangement of the water delivery system and valve opening mode，all hydraulic indexes can meet the requirements of the codes and design.