Rigorous current regulation requires decrease emissions from marine engines. It is difficult to test all technologies for marine engines using experimental methods. It is important to develop simulated models for alternative fuels. A semireduced kinetic mechanism can be constructed to investigate the performance of the marine diesel engine, which consists of 341 elementary reactions and 74 species. Then, the Directed Relation Graph with Error Propagation (DRGEP) and the sensitivity analysis methods were used to reduce this mechanism. The reduced mechanism consists of 279 elementary reactions and 62 species. The ignition delay times with the semidetailed and reduced mechanisms were validated with the experimental data. At the same time, the results were compared with the data of published mechanisms Good agreements of ignition delay times were obtained. It was also found that the trends of in-cylinder temperature, pressure, and main species mole fractions were almost the same as results of the published mechanism for the internal combustion engine model. The main polycyclic aromatic hydrocarbon (PAH) mole fractions are almost the same compared to experimental data, especially the species A4. The 62-species mechanism was validated with the experimental data in a marine diesel engine model. It can be seen that the in cylinder pressure was in good agreement with the experimental data. NOx had a 2.2% error compared with the,experimental data, which is the minimum error.