Gears are important basic parts in aerospace and other fields, as well as their processing quality is affected by the thermal characteristics of the machine tool. In order to explore the thermal state of the green dry hobbing machine, an identification method of temperature field characteristic combining multi-field coupling simulation and thermal imaging reconstruction is proposed. Based on the characteristics analysis of the multi-source heat flow of the dry hobbing machine, the temperature field simulation model of the dry hobbing machine with the coupling of structure-heat-fluid multiphysics is established. Then, combining thermal image reconstruction and simulation analysis, the temperature field distribution characteristics of dry hobbing machine are revealed and its key thermally sensitive parts are determined. On this basis, a multi-dimensional optimization strategy for temperature field distribution of dry hobbing machine is proposed. The results can provide theoretical support for the thermal balance design and thermal error compensation of dry hobbing machine.