Abstract: Aiming at the problems that the outlet flow is difficult to control, and the deposition layer size error is large during metal fused coating process, the flow field and pressure field of 2024 aluminum alloy melt in the coating nozzle were numerically analyzed. The velocity and pressure cloud diagrams show that sudden changes of flow field are mainly concentrated in the narrow channel of the outlet.Since the necked part of the nozzle can consume energy and relieve pressure, the maximum velocity increases when the outlet diameter increases from 0.3 mm to 0.5 mm under the same conditions. In order to ensure the stability of outlet flow, the pressure compensation value of the molten metal in the crucible should be equal to the pressure loss caused by liquid level drop.