In this paper we report the thermal performance of LED head lamp module and the cooling system. The precise fluid field modeling and heat transfer analysis using a CFD (Computational Fluid Dynamics) were performed according to the practical working conditions for the headlamp. The junction temperatures of LEDs were found to decrease by using the air cooling system and thus improved the heat dissipating capability of the LED array. The junction temperature of the LED array was decreased from 70.6 °C to 30.25 °C when the circulating speed of the air increased from 0 km/h to 120 km/h. And the temperature decrease of 2-4 °C was obtained by using fins. By the thermal analysis, a new thermal design was obtained for the cooling system of LED arrays for the headlamps. Thus the reliability of the headlamp with LED arrays can be improved with a good cooling system.