Experiments have been carried out to investigate the effects of operating parameters and coal types on the formation of HCN and NH3 during coal pyrolysis in a fixed-bed reactor system with temperature-programmed heating. Three coals from China and 2 coals from Australia, ranging in ranks from bituminous coal to anthracite, were used in these experiments. Our experimental results indicate that the formation of HCN and NH3 is affected by peak temperature, particle size, and gas flow rate. The effects of these operating parameters vary with the coal properties. In addition to coal rank, the petrographic composition and/or geographic origin of the coal are important factors influencing the formation of HCN and NH3 during pyrolysis.