The invention relates to an air/kerosene high-temperature gas generating device capable of continuously, quickly and linearly adjusting the temperature within a large range. The device is mainly composed of an auxiliary atomizing air and aviation kerosene atomizer, a first-stage air combustion chamber, a second-stage air combustion/mixing flame tube and a high-energy electric spark plug igniter, and a novel two-stage atomization and two-stage combustion/mixing working mode is adopted. During operation, the flow of auxiliary atomizing air is fixed, auxiliary air and aviation kerosene are mixed and sprayed by the atomizer, and first-stage air and atomized aviation kerosene are atomized, mixed and burnt for the second time through the first-stage combustion chamber; and second-stage air has the effect of cooling or secondary combustion according to the flow of the aviation kerosene. By adopting the two-stage atomization and two-stage combustion/mixing technique, the gas flow temperature can be adjusted within the large range from 700 K to 2100 K, and the gas flow temperature can be quickly, continuously and linearly adjusted only by adjusting the flow of the aviation kerosene.