Double involute gear drive was a new type of gear drive. Based on the theory of friction,heat transfer and gear meshing,the friction heat flux and convection coefficient of double involute gear were calculated,considering the heat energy of friction contact between teeth as heat source. The temperature field finite element analysis was carried out by using ANSYS finite element software. The maximum temperature variation law of gear tooth was obtained through the simulation of the temperature field of the double involute gear under different step parameters.