In order to reduce the emission of CO and NO, the combustion characteristics of flat flame were analyzed by using different air outlet arrangements. The experimental results show that: Both four-pipe and three-pipe air outlet arrangements can form a flat flame. The negative pressure areas caused by the air swirl reduces the return resistance. The high-temperature furnace gas flows back to the flame center and squeezes in the center of the swirl. As the distance from the air tube to the center axis of the burner increases, the flame surface gradually expands, thereby reducing the peak temperature of the combustion zone, which in turn promotes the reduction of CO and NO content; Under the same air tube distance, the four-tube tangent circle has a larger flame surface and a more uniform distribution than the three-tube tangent circle, and the peak temperature and the contents of CO and NO are slightly lower than the latter. It is concluded that the four-tube tangential arrangement is adopted, and the distance between the air tube and the central axis of the burner is appropriately increased, which is more suitable for the low-nitrogen combustion of the flat flame burner.