A new and high efficiency liquefied natural gas (LNG) vaporizer was developed.In the vaporizer,flue gas was used to impact a rotor at high speed,and to form rotating air flow including steam and water drops.When wet flue gas flowed cross an upper coil heat exchanger,heat transfer was enhanced because of phase change,and the vaporizer was operated safely because the temperature of wet flue gas was lower than LNG flash point.The influences of heat transfer characters,flue gas recycling degree and water level height on the flow and heat transfer of flue gas while impacting the rotor were theoretically analyzed and experimentally researched.By experiments, the heat transfer coefficients of coil heat exchangers and the optimum operating condition of the vaporizer were determined.