Abstract: The effects of temperatures and atmospheres on the sulfur transformation during pyrolysis of Liuzhi (LZ) raw coal and the chars (prepared by pyrolysis in a fixed bed reactor) were investigated by AP-TPR-MS combined with chemical analysis. The results show that only a small part of unstable organic sulfur in LZ coal can be removed by pyrolysis in the fixed bed reactor at 500℃ under N₂ atmosphere, but pyrite and unstable organic sulfur can be completely removed at 700℃ under N₂ atmosphere, and those sulfurs can also be removed at 500℃ under syngas atmosphere. The higher the temperatures, the greater the reactivity of sulfurs with syngas atmosphere, which is very similar to that under H₂ atmosphere. However, the sulfur removal is less under 1.0% O₂-N₂ atmosphere like that under N₂ atmosphere.