Detailed kinetic models are important to describe the oxidation of hydrocarbon fuels. In the present study, a detailed kinetic models has been developed to simulate the combustion of natural gas in IC engine. The proposed models consists of 208 elementary reactions and 72 species. The rate of the production and sensitivity analysis of the proposed reaction models were carried out to visualize the effect of reactions on the formation of various pollutants. In the rate of production analysis, an absolute rate of production coefficients and the normalized rate of production coefficients were calculated for the reactions involved in the formation of pollutant species (CO, NO, NO2, & NH3). In sensitivity analysis, normalized logarithmic sensitivity coefficients were determined the reactions of rates affects the output concentrations of the pollutant species. These two analysis were carried out for two temperatures ranges i.e. 1500 °C and 4000 °C under stoichiometric conditions (when φ=1.0).