In order to characterize the mechanics of jet breakup,the finite volume formulations were employed to solve the Navier-Stokes equations and continuity equation of jet.The volume of fluid (VOF) method was used to track the free surface of jet.The spray process of the molten Pb63Sn37 alloy was simulated based on the mathematical model by means of FLUENT code.The configuration of jets generated in different disturbance ratios and modulation ratios was obtained.The theoretical results show that the droplets merge together by the number of disturbance ratio N,which agrees with the corresponding picture captured in the experiment.In addition,the droplet streams broken at non-optimal frequency are also uniform according to simulation results,which proves that the A-M disturbance can increase the width of the uniform droplet generating frequency.