The utility model relates to a LNG air supply technology field discloses a LNG air feeder and LNG gas supply system, LNG air feeder includes: the pressure boost passageway is including consecutive first stop valve, first air -vent valve, first vaporizer, a pressure sensor and second stop valve, supply the liquid passageway, including consecutive third stop valve, first control valve, gasificationequipment, regulator, a temperature sensor and the 2nd pressure sensor, controller with first air -vent valve, a pressure sensor, first control valve, the 2nd pressure sensor and a temperature sensorsignal connection is used for: aperture according to a pressure sensor's the first air -vent valve of signal control, according to opening and shutting of the 2nd pressure sensor and a temperature sensor's signal control first control valve. Above -mentioned LNG air feeder's degree of automation is higher, need not the personnel guard, and can directly adopt LNG tank wagon or LNG removal tank to supply liquid.