Abstract: According to N-S equation,the author established control equation of two-dimensional water waves due to landslide,and solved equation with two-dimensional unsteady separation PISO algorithm.The movement of sliding mass is controlled by UDF programming and dynamic mesh technology.The nonlinear free-surface fluid field is tracked with VOF method,combined with RNG k-ε turbulence model.Via computational fluid dynamics software FLUENT,the velocity and height change of free-surface due to landslide are simulated,and the result is compared with the experiment of Monaghan and Kos’.The example shows that the model in this paper can properly simulate the generation and transition of solitary wave and formation of the vortex.On this basis,the paper further studies on the effects of landslide velocity on the deformation of free-surface.Therefore,the numerical simulation of sliding mass entering water can properly simulate the phenomenon of water waves generated by landslide due to the avalanche of reservoir dam,and provide the reservoir dam design and disaster prevention of water waves generated by landslides with very important reference value.