Since Taylor firstly put up with the confluence problem of rectangle open channel in 1944, the
hydraulic behavior at the confluence is already studied detailed based on theoretical analysis and sketch
model experiment at home and abroad[3~5], but the study on hydraulic behavior of natural river
confluence is not sufficient. The confluence of Yangtze River and Jialing River is the aquatic gate of two
river shipping in Changing, where the flow is so complicated and varied as to seriously endanger shipping
safety. The hydraulic behavior of the confluence of Yangtze River and Jailing River is researched in
detail by numerical simulation in this paper.