A low NOx combustion system used for reburning gasified coal gas partially consists of a gas reburning low NOx burner and a small pressurized entrained flow gasification device; air nozzles and fuel nozzles of the reburning low NOx burner are alternately arranged, each air nozzle is connected with a wind box, each fuel nozzle is connected with a respective fuel system, the fuel nozzles are arranged in the lowest air nozzle, two lines of gas nozzles are provided, and each line is provided with gas jet holes; all the nozzles are swinging and adjustable between within 30 degrees from the top to the bottom; the small pressurized entrained flow gasification device consists of a gasification furnace, an air lock feeder and a pressurized chamber and is connected by dedicated pipes, the coal gas at the upper part of the gasification furnace is introduced to the gas nozzles of the gas reburning burner, and carbocoal from the lower part enters a coal dust nozzles of the gas reburning low NOx burner. The low NOx combustion system can be used in thermal power stations which lack of combustible gas sources, the coal gas generated by the gasification furnace is reburned to realize coal dust burning with low NOx discharge, and the NOx discharge amount is less than 190mg/m<3>.