Abstract: In view of the problems of high quality requirements, small hole diameter, large number of holes and difficult processing, this paper proposes a short electric arc-electrolysis compound machining method for deep and small holes. Short electric arc-electrolysis machining has the advantages of material-independent, high processing efficiency and good surface quality, but due to the large flexibility of the cathode for deep and small hole machining, the processing is easy to shake and the arc discharge energy can cause poor chip discharge, short circuit and secondary discharge problems. In view of the above problems, this paper investigates the flow-solid coupling characteristics of deep and small holes by short electric arc-electrolysis compound machining. From the perspective of the gap flow field, the motion characteristics of the gap flow field under different feed rates and different machining depths are studied, and experiments are designed to verify the simulation results. The results show that in a certain range, the faster the feeding speed of short electric arc-electrolysis composite machining, the faster the average motion speed of interpolar medium, the more uniform the particle distribution, and the better the chip removal effect, therefore, by increasing the feeding speed can promote chip removal and improve the stability of short electric arc-electrolysis composite machining.