Simulation of the gas-liquid-solid three-phase flow field of outside the abrasive water jet(AWJ) nozzle is studied by the computed fluid dynamic software- FLUENT, and the velocity field of the three-phase flow is obtained, the velocity value of the flow between the nozzle and work-pieces is also obtained. Serial experiments have been done to verify the simulation method. In the experiments, the impact force signal of the AWJ outside the nozzle is collected by the piezoelectricity ergometer, then it is filtered by the vibration signal and dynamic signal software. The testing values are transformed to the velocity values, which will be compared with the simulation values. The comparison result indicates that the value of the simulation is changing similarly with the experiment value, and both value is almost the same, which proves that the simulation method is successful, the simulation model and the boundary conditions are right.