This study discusses numerical study of premixed hydrogen flames in confined/unconfined combustors. Within the scope of this study, combustion performances and emission characteristics of premixed hydrogen combustion have been performed by using a CFD Code. Modellings were implemented by changing excess air ratios from 0.8 to 1.7 for fixed heat input of 50 kW. Moreover, investigations were conducted in two different combustors (confined/unconfined) for better understanding of hydrogen combustion. According to the results, the maximum temperature distribution was emerged as about 2000 K in confined combustor. Although the maximum temperature value increases with increasing the excess air ratio until stoichiometric condition, the maximum temperature value decreases as the excess air ratio is increased after stoichiometric condition. Besides, simulation results were compared with experimental datas from the literature (diffusion flames). This comparison reveals that the general trend of the axial temperature profiles are in good agreement with the measurements. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.