In the present study, the implementation of a previously proposed reduced mechanism is examined through a CFD model by means of modified Kiva3V coupled with Chemkin II in a CFR natural gas fueled HCCI engine. Firstly, to investigate the accuracy of the reduced mechanism, its applicability was examined with experimental data. The model results with the reduced mechanism are in good agreement with experimental data. Then, after validation of the model, to further examine the validity of the reduced mechanism, 7 sets of different operating conditions were investigated. The in-cylinder pressure, peak pressure (Pmax), gross indicated mean effective pressure (gross IMEP), cumulative heat release (CHR), emissions, and the crank angle when 50% of heat is released (CA50) have been selected as representative parameters for evaluating the performance of the reduced mechanism. The results of the model demonstrated that the calculated representative parameters using the reduced mechanism are in good agreement with the detailed mechanism. Results reveal that the present reduced mechanism gives reliable performance for combustion, performance and emissions characteristics prediction, as well as computational time improvement for multidimensional CFD simulations from about 480 min to average 189 min for all cases on quad core 4 Intel CPU and 4 Gigabyte RAM personal computer. The reduced mechanism has 26 species and 63 reactions. (C) 2016 Elsevier Ltd. All rights reserved.