The invention relates to a hybrid power system with water-ethanol and hydrogen mixed fuel and a control method thereof. An exhaust pipe of an engine is connected with a hydrogen-enriched gas generator and then is connected with an engine silencer. A water-ethanol-contained storage box is filled with a water-ethanol-contained solution and is connected with a water-ethanol-contained pump. The water-ethanol-contained solution is conveyed to the hydrogen-enriched gas generator; the hydrogen-enriched gas generator splits alcohol into hydrogen; the split object enters a cooling and gas-liquid separator through an outlet of the hydrogen-enriched gas generator; the liquid obtained by separation enters the water-ethanol-contained storage box through a pipeline with a solenoid valve; and the hydrogen obtained by separation passes through a compressor and then enters a gas storage tank. An engine output line is connected with a controller and then is connected with an engine electric control board. The engine electric control board can receive an electric signal transmitted by a sensor, carries out storage, calculation, and analysis processing on the received signal, and then sends out an instruction to a valve body. The water-ethanol-contained storage box conveys the water-ethanol-contained solution to a mixer by the water-ethanol-contained pump; and after mixing with the hydrogen provided by the gas storage tank, the mixed gas is provided for engine for combustion, thereby pushing a cylinder to work.