Landslide surge can cause huge damage to the area of surge generation and propagation. The effect of the river boundary on the landslide surge in a river-type reservoir will result in wave superposition. In order to study the effect of river boundary on the surge period of landslide, a 3-d numerical model of landslide surge is established based on the FLOW-3D computational fluid dynamics software, using a physical model which is identical to the prototype of a river section in Wanzhou in Three Gorges Reservoir area. The methods of numerical solution, mesh generation and boundary condition setting are given, and the consistency of the three-dimensional mathematical model is verified by physical model test results. According to the three working conditions that the water entry point of the landslide body is located in the straight section of the river channel, at the crest of the convex bank and at the crest of the concave bank of the curved channel, the relation graphs of spectrum intensity and frequency are drawn. The influence law of the complicated river boundary on the surge period of the landslide is analyzed, and the effects of different bank slopes, curvature of curved concave bank, arc angle of concave bank and arc angle of convex bank on swell period are obtained.