The invention discloses a high-speed arc discharge, flushing and rotating main shaft device which comprises a mandrel, a shell, a conductive bearing, a conductive disc, an insulating bearing, an insulating flange, a belt wheel, a rotating connector and the like. A main shaft structure capable of rotating, discharging and flushing is given to achieve the purposes of circulating and supply of high-pressure fluid, rotating and conducting, and the problems of discharge corrosion and the like are solved. According to the high-speed arc discharge, flushing and rotating main shaft device, the light-weight design that the insulating bearing is matched with the mandrel in a supporting mode is adopted, the rotating speed of a main shaft is increased, the accuracy of the main shaft is improved, and the insulating reliability of the main shaft is enhanced; the hollow mandrel structure is combined with the rotating connector to achieve the purposes of high-pressure fluid supply and sealing; the rotating conducting defect that overcurrent capacity of an electric brush is limited, or the rotating speed of a conductive sliding ring is low, or a structure is enormous and complex is overcome; the rotating conducting difficulty is lowered to the maximum degree, and the cost is lowered to the maximum degree. The high-speed arc discharge, flushing and rotating main shaft device is simple in structure, convenient to maintain, low in maintaining cost and capable of being effectively used for various discharging milling including electric arc machining.