Aimed at the effect of scouring by moving water jets in a short time during the desilting process of sediment,this paper used smoothed particle hydrodynamics (SPH) to simulate the initial phase of scouring on sand beds by submerged plane vertical water jets. It discussed the method of building the submerged condition and the sand material in SPH, studied the development trend of dynamic scour depth and analyzed the effect of the jet velocity on scour hole depth.The result indicated that SPH method can effectively simulate the process of scouring by submerged water jets. In the initial phase,the scour depth increases linearly with time,and accelerates with the jet velocity.This study can provide a reference of simulation method for investigating the effect of soil failure by dredging water jets.