Sediment transport due to tsunamis causes various damages, e.g., salt damage, destruction of coastal protection facility, shoaling navigation channel in port, blocking water intake in power plant. These damages are extended over a long period and hamper rescue and restoration. On the other hand, tsunami deposits include valid information on historical and prehistoric tsunamis, and so they are useful for tsunami risk assessment. For the tsunami disaster mitigation purpose, the numerical model on tsunami sediment transport becomes essential recently. In this paper, the numerical model is reviewed and its problems are discussed.