Using a chemical reaction dynamics software of CHEMKIN and the CFD software, the influences of T, W/C, O/C and catalysts activity density on methane conversion, carbon deposition and the yields of H-2, CO and CO2 are investigated in the reaction of autothermal reforming of methane in a micro-reactor. The results show that optimum conditions of methane autothermal reforming are the oxygen carbon ratio of 0.4, the water-carbon ratio of 2.1, the temperature of 1073 K, the flow velocity of 1 m/s and the catalyst active site density of 9.98 x 10(-6) kmol/m(2). Under these conditions, the methane conversion rate, the yields of H-2 and CO are 93-99%, 65-80% and 50-65%, respectively. The total carbon deposition is about 1.65 x 10(-12) kmol/m(2). Moreover, the investigation and development of the three-dimensional spiral multi-cylinder micro-reactor are essential for applications of the mobile fuel cell in the Micro-Electro-Mechanical Systems (MEMS) field. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.