The branch of Baguazhou is a typical goose-head shape branch river, with the branch on the left and the main on the right. Main branch is in right. Recently, due to the scouring and siltation at the bar head and increasing development and utilization of the river bank, wharves along the river increas and the division ration of the left branch reduces gradually, which is closely related to the impact from the resistance by the wharfs’pile groups. This paper studies the accumulative influence of wharf忆s pile group on the division ration by a 2-D flow mathematic model. The result reveals that with the building up of wharves, the flow resistance increases and the division ratio of the left branch decreases remarkably.