Abstract: The consequences of landslide waves are far beyond the landslide itself that has attracted widespread attention. The prediction and evaluation of this kind of disaster has always been difficult, and the precise description of landslide surge motion characteristics and energy conversion law is the key and premise to solve the problem. In this paper, we use gravel to mimic granular landslide and establish a 3D landslide wave model in a rectangular flume, aiming to analyze how the landslide volume, velocity and water depth affect landslide accumulation, wave characteristics and energy conversion. The results show that (1) the waves generated by solid impacting the water are affected by the landslide size and shape. Slides with larger thickness and faster speed tend to produce nonlinear transition wave, and thin and slow slides generally produce nonlinear oscillation wave. (2) The volume effect and velocity effect based on the test reveal that the surge scale of a certain water depth is positively correlated with the landslide volume and velocity. The water depth effect explains the differences of waveform and velocity under a certain wave energy. Statistic results show that under the shallow water conditions, surge height on average is 67% higher and wave speed on average is 51.17% higher than those under the deep water conditions. (3) The conversion rate between landslide energy and wave energy ranges from 1.00% to 3.07%. 3D experiments encounter more energy dissipation due to diffusion and its conversion rate is lower than that in the 2D experiments. This study discusses the kinematic characteristics of granular landslide, first wave generation, propagation and inundation, and proposes the basic law of energy conversion between landslide and water. It id of certain value and significance for landslide wave hazard prevention and mitigation.