A new skeletal mechanism for n-decane oxidation was developed based on a decoupling methodology with the special emphasis on the engine-relevant operating conditions from low to high temperature at high pressure. With the decoupling methodology, an extremely simplified model for C-2-C-10 was used to simulate the oxidation of heavy hydrocarbons for prediction of the ignition characteristics, while the mechanism of H-2/CO/C-1 was considered in details for providing accurate information of laminar flame speed and extinction strain rate. The new skeletal n-decane oxidation mechanism consists of 40 species and 141 reactions. Extensive validations of the present mechanism were performed by comparing with the experimental data available in the literature on n-decane oxidation, including ignition delay in shock tube and rapid compression machine, species concentrations in jet-stirred reactor and variable pressure flow reactor in wide ranges of temperature (550-1800 K), pressure (1-80 bar) and equivalence ratio (0.5-2). Moreover, the experimental data on the profiles of species concentration, laminar flame speed and extinction strain rate in premixed flame and counterflow flame was also being used in the validations. Finally, the skeletal n-decane mechanism was applied to predict the combustion and emissions of premixed charge compression ignition (PCCI) engines by using the multi-dimensional simulation. Overall, the current prediction from the present mechanism shows a good agreement with the experimental measurements, which indicates the potential of the decoupling methodology for the development of oxidation mechanism for heavy alkanes. (c) 2013 The Combustion Institute. Published by Elsevier Inc. All rights reserved.