The degradation mechanism of benzo[a]pyrene (BaP), a representative component of coking wastewater, and the pathway for the production of H-2 and CO in supercritical water have been investigated via ReaxFF reactive molecular dynamics simulations. The BaP molecules in the SCWG, SCWPO and SCWO systems show different degradation pathways. The maximum H-2 yield is obtained at the oxygen ratio of 0.2. There are three routes for the generation of H-2 molecules and production from H radical-rich water is the main route. CO molecules are formed by the C-C bond breakage and C-O bond breakage in the reforming fragments. There is a time delay between the fuel gas generation reaction and the side reactions due to the change of the instantaneous concentrations of H-2 and CO, providing a possible pathway to increase the amount of the produced fuel gases by designing a suitable reactor and recovering the gas fuel in time. Finally, kinetic behaviors of coking wastewater have been analyzed. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.