Abstract For high-power light-emitting diodes, heat management and reliability are important issues. The reliability and long lifetime of solid state lighting are especially essential in the high temperature applications, such as street lighting and automotive lighting. Because of the characteristics of semiconductor, the electrical property of light-emitting diodes is varying with operating temperature. Then, the alternation of electrical property changes the heating power and operating temperature of light-emitting diodes. This is a mutual interaction between electrical property and operating temperature, until they reach the steady state. In this paper, we designed experiments and calculation to optimize the simulation of temperature distribution of light-emitting diode module. With forward voltage measurement and thermal transient testing of light-emitting diodes, we obtained the initial values of simulations. The infrared camera captured the thermal images to verify the simulation results. With this method, we can effectively evaluate the temperature distribution of light-emitting diode module.