A coupled system simulating both firebox and reactor is established to study the naphtha pyrolysis in an industrial tubular furnace. The fireboxmodel is based on zonemethod including combustion, radiation, and convection to simulate heat transfer in the furnace. A two-dimensional recirculation model is proposed to estimate the flow field in furnace. The reactor model integrates the feedstock reconstruction model, an auto-generator of detail kinetic schemes, and the reactor simulation model to simulate the reaction process in the tubular coil. The coupled simulation result is compared with industrial process and shows agreement within short computation time. (C) 2017 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.