A comparison study of the oxidation of n-propylbenzene (NPB), iso-propylbenzene (IPB), 1,3,5-trimethylbenzene (T135MB), 1,2,4-trimethylbenzene (T124MB) in a same jet-stirred reactor was performed to find a most suitable transport fuel as a surrogate component. The experimental results show that IPB with the weakest C-H bond tends to be the most active fuel among the four C9H12 fuels, while T135MB is the slowest. Ten common intermediates detected in all experiments and eight characteristic intermediates were comprehensively compared, including hydrocarbons, aromatics and oxygenated species. NPB and IPB tend to produce more hydrocarbons and benzene, while T124MB and T135MB generate more toluene and acrolein. Based on the previous studies, an universal mechanism was presented by involving the four sub-mechanisms with good prediction on the measured results. The rate-of-production analysis shows that H-abstraction on the methyl or propyl is the dominant consumption pathway of C9H12 fuels, while C9H11 radicals maintains bigger differences than the initial reactions. Sensitivity analysis shows that CH3 is the key intermediate in the consumption of propylbenzenes, and OH plays similar role in the oxidation of trimethylbenzenes. Moreover, the production pathways of the aldehydes and PAHs in the oxidation were also discussed to understand the pollutant formations. Benzyl and styrene are believed to be the main precursors of aldehydes and PAHs, respectively. In general, these results provide better understanding of the oxidation and combustion of C9H12 fuels as potential surrogate fuel constituents for kerosene and diesel. Furthermore, the comprehensive experimental and modeling studies of C9H12 fuels could also offer the guidance function for the surrogate component selection. (C) 2019 The Combustion Institute. Published by Elsevier Inc. All rights reserved.