The invention relates to an air heating device for a high-temperature and high-pressure kettle. At present, the way of obtaining high temperature is achieved by convective heat transfer of heat transfer oil at home and abroad. It has the following disadvantages: easy to leak, low thermal efficiency, poor controllability, poor furnace temperature uniformity, slow heating and cooling, and relatively low comprehensive performance parameters. Difference. The invention includes a kettle body, a heater, a fan, a thermal insulation layer, and an air guide tube. The thermal insulation layer includes an outer shell, an intermediate thermal insulation cotton, and an inner layer plate; An air duct is provided, and the air duct is divided into an inner air duct and an outer air duct through the air guide tube, and a heater is installed in the outer air duct; the air outlet of the inner air duct and the air inlet of the outer air duct are arranged at the lower end of one side of the insulation layer, It is connected by a fan to form a hot air circulation channel. The invention has the advantages of small heat loss, low thermal efficiency, few maintenance points, strong controllability, good temperature uniformity, fast heating speed, rapid cooling, and good comprehensive performance parameters.