Abstract: Study the effect of excess air coefficient,de-oxidation additive amount on NOx emission with the help of coal water mixture organic heat transfer material heater whose type is YJW5900-J and the flue gas analyzer（testo-350XL-Germany）.The results show that,without additional reductive reagent,the selectivity un-catalytic reaction of coal water mixture goes well,the NOx emission can be controlled by adjusting the excess air coefficient.This method guarantees that the NOx emission meet the national discharge standards.