The invention relates to an airtight type fuel air heater. The heater comprises a machine box shell body, wherein a cold air inlet is formed in one side face of the machine box shell body, a hot air outlet is formed in the top surface of the machine box shell body, an electric part assembly is arranged in the middle of the machine box shell body, the electrical part assembly comprises an electrical part mounting board, the electrical part mounting board is provided with a transformer, a controller, a rectifier bridge and a filtering capacitor, a heater core assembly is arranged at the lower part of the machine box shell body, one end of the heater core assembly is connected with a fan, the fan is arranged at one end, close to the cold air inlet, of the heater core assembly, the other end of the heater core assembly is connected with the hot air outlet through a pipeline, an oil tank assembly and an electromagnetic pump assembly are arranged outside the machine box shell body, and the electromagnetic pump assembly is arranged below the oil tank assembly. The airtight type fuel air heater has the beneficial effects that the labor intensity of workers is reduced, the structure of theheater box body is good in overall gas tightness, the heating value is large, the overall stability is good, the shock resistance is good, the heater can realize remote operation to facilitate the operation of the personnel.