Abstract: The NOx emission of bituminous coal in the temperature range of 1 000-1 600 ℃ was studied with a two-stage dropper tube furnace at high temperature. The purpose is to study the effects of the temperature of primary combustion zone and excess air coefficient with staged low nitrogen combustion technology. The results show that NOx emission in- creases with the excess air ratio when the temperature of primary combustion zone is in the range of 1 000-1 600 ℃ . However,the increasing extent of NOx emission was reduced when the excess air ratio exceeds 1. This is of great impor- tance in the engineering practice. The excess air ratio required is becoming smaller with the increase of the temperature of primary combustion zone,and thus the waste heat loss will be reduced. When the temperature of primary combustion zone is in the range of 1 000-1 400 ℃ ,the optimal excess air ratio of primary combustion zone is 0． 786,while 0． 69 for the range of 1 500-1 600 ℃ . The removal rate of NOx increases from 80% to 96% when the temperature of primary combustion zone increases from 1 000 to 1 600 ℃ . There is a positive correlation between temperature of primary com- bustion zone and NOx removal rate. When the temperature of primary combustion zone is in the range of 1 400-1 600 ℃,the ratio of thermal NOx to the total NOx tends to decrease with the increase of excess air ratio.