Abstract: Realistic modeling and rendering of natural catastrophic scenes has been found great applications in the areas such as disaster prevention & rescue,special effects in movie and TV production,digital entertainment,etc.This paper describes a new physically based multi-phase flow model to simulate natural catastrophic phenomena,such as flood,debris flow and landslide.We first establish a dynamic model of multi-phase flow with different stages according to the cause of formation of all those natural catastrophic phenomena,and then extend the traditional smoothed particle hydrodynamics(SPH)method to realize the interaction between solid phase and liquid phase.By adjusting the ratio of solid volume fraction and other characteristic parameters,we successfully simulate the dynamic flow of flood,landslide and debris flow with different mixtures and demonstrate the process of multi-phase flow destroying buildings vividly.