Abstract: Minerals inherently presented in coal and ironcontaining compounds externally added have an important influence on the formation and release of HCN—one of the NOx precursors during coal pyrolysis. The experiments on the pyrolysis of raw coal and demineralized coal with different carbon contents and ironcontaining compounds were carried out in a fixed bed quartz reactor with the temperature programmed. The influencing factors of HCN formation and release during coal pyrolysis were examined. The results show that the effect of ironcontaining compounds in coal on HCN release depends on the coal types. And the iron added to coal by impregnation and precipitation method can significantly reduce the formation of HCN for lower coalification coals . Additionally, the effects of particle size and reaction time on HCN formation during pyrolysis of coal with iron were also studied.