in the short arc machining process, a large number of etched particles will be distributed in the bottom and side narrow gap, forming a "rich area".When the etched material cannot be removed in a timely manner, it will cause the change of the inter-electrode discharge state and cause "secondary discharge", which will lead to the reduction of the workpiece precision and the loss of the electrode.In this paper, FLUENT software was used to carry out simulation research on the distribution state and removal mode of the etched particles in the narrow gap in the short arc milling process, and DPM model was selected for particle tracking calculation.By simulating and studying the distribution law of particles in narrow gaps at different machining depths and verifying with experiments, it is concluded that the change of machining depth has no significant influence on the surface quality of workpiece. When the machining is 3mm, the flow field velocity is large and the particles are thinly distributed at the corners, which is conducive to chip removal and improves the stability of short arc machining.