In this work, density functional theory (DFT) was employed to investigate the reaction pathways of beta-D-glucopyranose for better understanding the pyrolysis mechanism of cellulose in hydrogen plasma. Many possible reactions were considered, and the reaction enthalpies and activation energies of these reactions were calculated using density functional theory (DFT) with a Gaussian method of B3LYP and basic set of 6-31G(d,p). A most possible reaction pathway was brought up. According to this reaction pathway, the main products of cellulose pyrolysis in hydrogen plasma would be syngas, and few light hydrocarbons. CO mainly comes from the decomposition of aldehyde group, while H-2 mainly comes from dehydrogenation processes. Active H. in plasma are found to play a very important role in many reactions, and they can remarkably lower the energies needed for reactions. (C) 2013 Elsevier Ltd. All rights reserved.