The floating ice block which submerge under the ice cover are called submerged ice block. The stagnation and accumulation of the block might cause the hard ice situation phenomenons such as ice jam and ice dam. The movement of submerged ice block is closely related to the hydrodynamic forces of bottom. The Realizable k-ε turbulence model was applied to establish the 3-D numerical model for studying the pressure distribution at bottom of submerged ice block. The comparison between numerical simulation results and Larsen’s physical model experimental results was conducted and they were in good agreement, which proved that the simulation results were reasonable and reliable. The pressure at the bottom was the combined effect of Venturi pressure and leading-edge effect. The simulation results showed that the Venturi pressure and leading-edge effect not only depend on the thickness-to-depth t/h ratio and the relative width b/B ratio, but also vary with the flow velocity V under the ice cover. The Venturi pressure is positively correlated with b/B, while the leading-edge effect is exponentially correlated with b/B. The equations of Venturi pressure and leading edge effect which related to the width of submerged ice blocks are concluded after analyzing the numerical simulation. On the basis of the equations, the paper put up the pressure computational formula at bottom of submerged ice block.