The tributary entrance of tidal reach is affected by the tidal action. Due to abrupt change of the local junction building section，a variety of adverse flow patterns are produced during high-intensity water diversion at low tide，which seriously decreases the flow capacity of the lock gate. Taking the Jiepai Junction of the Xinmeng River as an example，we carry out the physical model optimization experiment of local flow condition，and propose the scheme of regulation measures of the different barrier wall lengths and diversion pie forms. The results show that the extension of the barrier wall can only advance the backflow position and increase the backflow length，but it has no obvious effect on the flow pattern of entering the lock. The parallel arrangement of the diversion pier can make the flow zones of each pier non-overlapping and connect well. The scheme of 10 m extending of the inner left pier leads to a more uniform flow velocity distribution.