Based on CFD software and reaction kinetics software, multi-dimensional CFD Model coupled with detail reaction kinetics is built to study the combustion process in H 2 /CNG Engine. Detail reaction mechanism is used to simulate the chemistry of combustion and a combustion model considering the turbulent mixing effects was also applied. To reduce the computation time, the coupled software is reprogrammed to have the function of parallel computing and the revised software is computed in a Massively Parallel Processor. The model is validated using the experiment data from a modified diesel engine. The results show: cylinder pressure from simulation has a good agreement with experiment data and CO and NO x emission is well predicted by the model in a wide range.