Abstract: Submarine landslides generally have the characteristics of large volume, fast flow velocity, and wide impact range, and are a highly destructive marine geological hazard that poses a great threat to marine engineering. During the propagation of submarine landslide, there is a violent interaction between the landslide body and surrounding water, and traditional numerical methods are difficult to simulate this complex process. Based on the Smooth Particle Hydrodynamics (SPH) method, this paper applies the Herschel Bulkley viscous fluid model and the classical Newtonian fluid model to simulate the landslide and its surrounding water, respectively. An SPH multiphase flow model is established for the submarine landslide, and the stability of the model is improved through the artificial diffusion term of density and the modification of the state equation. Through the simulation of the submarine landslide model experiments, the accuracy and applicability of the SPH model are verified, and the influence of rheological parameters on landslide propagation characteristics is explored. Finally, the SPH multiphase flow model established in this paper is used to simulate the motion process of the Zhujiajian submarine landslide, analyse the interaction mode between the landslide body and surrounding water, and predict its sliding velocity and runout distance. This study can provide scientific basis for the prevention and mitigation of submarine landslide disasters.