Chlorine is rich in biomass and some coals and significantly released as HCl(g) during combustion process, and this promotes the recombination of free radicals OH, H, O, and HO2 and further influences CO oxidation. In this paper, the inhibition effect of HCl on CO oxidation is investigated by experiment and numerical simulation. The experiment is operated under different reaction zone temperatures and equivalence ratios in an entrained flow reactor. And the numerical simulation is conducted by CFD software coupled with reduced reaction mechanism. The results indicate that HCl addition obviously inhibits CO oxidation under oxygen-rich condition, and the inhibition enhances as HCl concentration rises, but weakens as temperature increases. Under chemical equivalent and oxygen-lean conditions, the inhibition effect is limited. (C) 2016 Elsevier Ltd. All rights reserved.