Abstract: In response to solve serious problems of air pollution,China has accelerated the implementation of the " coal-to-gas" policy in recent years. Coal-fired boilers have been gradually replaced by gas-fired boilers. It is important to develop and design the new low-nitrogen gas burners. In response to the national call of " low nitrogen and environment protection",a new micro flame low nitrogen burner was proposed. Numerical simulation method was used to optimize the corresponding aperture structure of the burners,and on this basis,the combustion conditions were simulated to select the optimal combustion conditions. The results show that as the air inlet diameter increases from 16 mm to 22 mm,the air flow rate slows down due to the diameter increase,the combustion time of the mixed reaction of gas methane and air becomes longer,and the combustion releases more heat. When the diameter continues to increase,because the small flame has a larger heat dissipation area and the heat is dissipated to the surroundings,the temperature in the high-temperature area at the center of the flame first increases and then decreases. The burner burns clean fuel methane,and the produced NO_x is mainly thermal NO_x that is greatly affected by temperature. Therefore,the amount of NO_x generated first rises and then falls. With the increase of excess air from 1.1 to 1.4,the high temperature area in the center of theflame obviously decreases,the temperature also decreases from 2 270 K to 2 042 K. As the temperature in the high temperature zone in the furnace decreases and the residence time of air in the high temperature zone becomes shorter,the production of NO_x decreases from 412 mg/m~3 to 52 mg/m~3. In conclusion,the new low nitrogen burner has a good combustion effect and can effectively reduce NO_x emission. Moreover,when the methane inlet diameter is designed to be 2 mm,the air inlet diameter is designed to be 16 mm,and the excess air coefficient is set to be 1.4,the new low-nitrogen burner can achieve low NO_x emission.