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