In this study, several n-type electrode patterns were designed to evaluate the current spreading effects in high power ThinGaN light emitting diodes. A proposed three dimensional numerical simulation was used to investigate the current spreading distributions. The experimental current spreading tendencies in various n-type electrodes were consistent with the simulation results. The maximum lighting output power was enhanced to 11% in our electrode pattern designs. The current-voltage and luminance-current performance of LED chips can apparently be improved with a better current spreading distribution. Therefore, this three dimensional simulation method could be used for the advanced analysis and optimization of LED performance. (C) 2010 Elsevier Ltd. All rights reserved.