The mechanism of detailed chemical reactions in combustion is very complicated, especially when the formation of a pollutant such as NOx is considered. Based on regression analysis, a simplified fuel-NOx model is developed for premixed flame. The new model iS available for a wider range of temeperature and fuel-air ratios compared with De Soete's (1975) fuel NO model. The reduction CHi species on NO iS considered so that the model can be used in both fuel-lean and fuel-rich combustion systems. After a great simulation of a one-dimensional premixed flame system using Miller and Bowman'S (1989, Prog. Energy Combust. Sci., 15, 287) detailed elementary reaction model, the calculation of all the reaction rates is presented based on regression analysis.Copyright