Abstract: Simulate the combustion process in methane combustion furnace using the computational fluid dynamics software FLUENT.With the establishment of mathematical model,investigate the temperature and NOx emission under different preheated air temperature,oxygen concentration in the air,excess air coefficient and nozzle diameter.On that basis,further study the furnace operating and structural parameters on combustion performance,thus providing guidance for combustion improvement and pollutant emissions reduction.The results show that,high temperature and low oxygen combustion,keeping the excess air coefficient from 1.0 to 1.3 and smaller nozzle diameter all are conducive to combustion process and make the combustion furnace temperature distribute uniformly,therefore reduce NOx emissions.