In order to optimize the traffic organization of the cross-river channel at entrance ramp，the two-layer planning model was used to calculate the optimal diversion ratio of the entrance ramp. The upper planning target was the road network with the greatest matching，and particle group algorithm was used to solve. The lower model was the user equilibrium model，which was solved by F-W algorithm. Taking the Xiangfu Road Bridge in Changsha City as an example，The travel time， smoothness，road traffic state and intersection traffic state were utilized to evaluated the matching between the river-crossing channel and the road network. The traffic diversion scheme of the ramp under different traffic needs is released. The result shows the ramp control method for river crossing channel based on optimal matching can effectively alleviate local congestion，that has has strong operability.