The goal of this study is to improve the thermal characteristics of high-power LED (light emitting diode) package by using a loop heat pipe. The heat-release characteristics of high-power LED package are analyzed and a novel loop heat pipe (LHP) cooling device for high-power LED is developed. The thermal capabilities, including start-up performance, temperature uniformity and thermal resistance of loop heat pipe under different heat loads and incline angles have been investigated experimentally. The obtained results indicates that the thermal resistance of the heat pipe heat sink is in the range of 0.19-3.1 K/W, the temperature uniformity in the evaporator is controlled within 1.5 degrees C, and the junction temperature of high-power LED could be controlled steadily under 100 degrees C for the heat load of 100 W. (C) 2009 Elsevier B.V. All rights reserved.