This investigation involved the formation and release of precursors of NO x , which were HCN and NH 3 , during gasification of coal and its char. Gasification was carried out in a fixed bed reactor at atmospheric pressure. The reactor allowed coal particles to be heated up rapidly and held for a pre-specified period of time at peak temperature. The influence of coal rank and coal particle size on the release of N-containing compounds during coal gasification with CO 2 is discussed. Gasification agents and coal gasification temperature were two key factors on the amount of nitrogenous compounds released. Results showed that with an increase of reaction temperature a great amount of NH 3 was formed during gasification with steam: The yield of NH 3 was highest at 800 o C during gasification with CO 2 . The volatiles in coal played the key role in the formation of HCN and NH 3 during coal gasification under steam atmosphere. Volatiles were the main source of the formation of HCN and NH 3 , mainly from the nascent char thermal cracking, whose procedure could be promoted by H 2 O(g): The yield of HCN during coal gasification had no strong relation with gasification agents and increased with an increase in gasification temperature. A reasonable mechanism for the formation of nitrogenous compounds during coal gasification was suggested in this study, which could explain some results in the literature on pyrolysis and gasification of coal.