A density functional theory (DFT) study has been conducted in this work to investigate the mechanism of methanol conversion using cold plasmas. All pathways for initial methanol dissociation were analyzed. The feasibility of the production of various products, including hydrogen, carbon monoxide, and ethylene glycol (EGL), was discussed. The present DFT study confirmed that the major obstacle of methanol conversion to either hydrogen or EGL is the dissociation of methanol. After the cold plasma provides necessary energy for methanol dissociation, hydrogen and EGL can be easily obtained without any thermodynamic obstacles. The calculation shows that EGL can be synthesized from the coupling of CH2OH center dot radicals, which can be principally generated from methanol dissociation and from the reaction of H-center dot + CH3OH. If the energy of electrons within cold plasmas could be controlled to be no more than 100 kcal/mol, the further dissociation of CH2OH center dot radicals, the re-decomposition of EGL, and the production of H-2 and CO through complex steps would be effectively reduced. By this way, the yield of EGL can be increased.