One of the most important challenges on implementing Diesel Dual Fuel (DDF) engine into the vast market is CH4 emission in its exhaust. This is due to the fact that CH4 is hard to oxidize at lower temperature environment of DDF exhaust comparing to that of conventional or bi-fuel engines. In addition, another parameter such as exhaust flow rate, specie concentration, especially CO, C3H8, and water have tremendous impact on Diesel Oxidation Catalyst performance on reducing CH4. Combining of all these factors together, a study of CH4 reduction is a major research problems that researchers around the world are keen to gain more fundamental understandings. In this work, a new CH4 kinetic model, which is based on Langmuir Hinshelwood mechanism, including CO, C3H8, and water is implemented into 1-D and 3-D Catalytic Converter models. The CH4 kinetic model is calibrated with the experiment by using synthetic exhaust gas generator. The composition of synthetic gas is mimic to the exhaust gas from diesel dual fuel engine. Once the model is well calibrated, a parametric study is done to investigate the validity of the model.