Short electric arc milling (SEAM) involves the complex coupling between the high-density heat output of the arc, the high-speed rotation of the tool electrode, and the high-pressure flushing fluid inside the tubular electrode. To improve the arc discharge utilization, this study investigates the effects of mechanical action, fluid action, and mechanical-fluid coupling action on the arc breakage of short arcs via experiments. It is found that the high-speed rotation of the electrode reduces the adsorption of the working fluid to the electrode surface, which can help to reduce the recast of molten metal on the workpiece surface and improve the surface quality. The coupling of the two makes a greater contribution to arc breaking and molten metal removal, while also improving the spatial continuity of the arc discharge. Moreover, after SEAM based on the mechanical-fluid coupling effect, the nickel-based alloy GH4169 is found to have lower surface roughness, lower tool electrode wear, a higher material removal rate, and a thinner recast layer.