The invention discloses a low-nitrogen combustor, and belongs to the technical field of boilers. The low-nitrogen combustor comprises a barrel cavity, a combustor control assembly and a transmission assembly, wherein the combustor control assembly and the transmission assembly are arranged inside the barrel cavity, the combustor control assembly is provided with flame branch pipes and rail sleeves, the rail sleeves are arranged at the right ends of the interiors of the flame branch pipes, stepping gear rods are arranged at the right ends of the outer parts of the flame branch pipes, stepping screw rods are arranged at the left ends of the stepping gear rods, stepping nuts fixed on the barrel cavity are connected to the outer parts of the stepping screw rods through threads, and the transmission assembly comprises a power gear, a transmission rod, a cross coupling and an adjusting rotary rod. According to the low-nitrogen combustor, the flame direction and the flame length of nozzles ofthe flame branch pipes can be adjusted by controlling the rotation and the movement of the flame branch pipes, and finally the flames of the nozzles of the flame branch pipes are adjusted to the optimal state matched with a combustion chamber, so that the FGR flow is effectively reduced, and energy conservation and emission reduction are realized.