Abstract: In order to solve the problems of unstable machining and low machining efficiency in the internal-external flushing mode of short electric arc and electrochemical compound machining, this paper proposes an external air-internal liquid flushing mode that is more suitable for short electric arc and electrochemical compound machining. In the machining process, high pressure air is injected into the side to realize the combination of short arc machining and electrochemical machining in the machining gap, improve the gap flow field distribution, and improve the efficiency of short electric arc and electrochemical compound machining and workpiece surface quality.Based on Fluent software, the flow field simulations of internal-external flushing and external air-internal liquid flushing were carried out to analyze the effect of flushing of side high-pressure gas on the flow field distribution of the gap and the electrical conductivity of the medium. The material removal rate, unit energy consumption volume ratio and surface thermal damage layer under the two flushing forms were investigated by comparative experiments. The results show that the material removal rate (MRR) of the external air-internal liquid flushing mode can reach 750 mm³/min, which is 1.9 times higher than that of the internal-external flushing mode, and the unit energy consumption volume ratio is only 149.98 kJ/cm³, and the surface of the workpiece is free of recast layer after machining, and the dimensional accuracy is also greatly improved, realizing the machining of material without recast layer.