Abstract: Submarine landslides are one of the most hazardous agents,through which vast volumes of sediments are transported across the slopes under very high velocities. Hydroplaning is attributed to be the main reason for the high mobility of the submarine landslide,in which complicated interactions between the sliding mass and the ambient water is involved. This paper investigates the consequences of the hydroplaning using a novel numerical tool,the material point method(MPM),simulating the runout process of a laboratory and a real case submarine landslide. Considering the mechanical properties on the sliding mass during the runout process,upper drag force,basal resistance,and resistance from the water cushion are imposed on the sliding mass. The obtained runout distances for the two scenarios agree well with the observations. Based on the further analysis of the mobility of the sliding masses,it is found that the hydroplaning effect significantly enhances the runout distance and maximum velocity.