The invention provides a power device of an electric automobile. The power device comprises an engine, a generator, a rectifier, a storage battery, an inverter, an electromotor and a control system, wherein the engine comprises an acetylene generator, an acetylene oil pusher, a hydraulic motor, a circulating oil tank and a waste gas absorber; the acetylene generator is used for generating acetylene by utilizing calcium carbide and water; acetylene enters the acetylene oil pusher and is mixed with air and then ignited to generate high-pressure fuel gas to push hydraulic oil in the acetylene oil pusher out; the hydraulic oil enters the hydraulic motor to push the hydraulic motor to work; the hydraulic motor is used for outputting power through a gear shaft to drive the generator to generate power; then the storage battery is charged through the rectifier and supplies power to the inverter; the inverter outputs three-phase alternating current to drive the asynchronous electromotor so as to drive wheels; burning waste gas exhausted from the acetylene oil pusher enters the waste gas absorber; and after carbon dioxide is absorbed by an alkaline solution discharged by the acetylene generator, other harmless waste is exhausted to atmosphere.