In order to analyze the temperature characteristics in the meshing process of the cycloidal gear and study the influence of different modification methods on the cycloidal gear temperature,the distributions of contact stress and friction heat on the gear teeth before and after the cycloidal gear modification were compared and analyzed on the premise of the same radial clearance,considering the three commonly used combination modification methods of the cycloidal gear.Using finite element analysis,the temperature distributions in the temperature field before and after modification were calculated.The results show that the steady state temperature of the cycloidal gear can be effectively reduced by profile modification;in combination modifications,the optimal modification mode with the best cooling effect is positive isometric+positive displacement correction;the density of temperature gradient on single tooth increases with the decrease of meshing range;the maximum values of the instantaneous friction heat before and after the cycloidal gear modification are not affected,and the location of the peak value will change,while the peak value of the periodic friction heat is located at the same meshing phase angle of the gear teeth,but the value will increase with the increase of the pressure on the gear teeth.