Abstract: The effects of temperatures and atmospheres on sulfur transformation during pyrolysis of Zunyi (ZY) raw coal and its chars were investigated by AP-TPR-MS combined with chemical analysis. The results show that stable organic sulfur is the main sulfur form in ZY coal. Pyrite can be removed under all the atmospheres in the tests, except for nitrogen at 500 ℃. 1% O2-N2 atmosphere has strong reactivity to remove the stable organic sulfur in ZY coal, especially at 700 ℃. Under 1% O2-N2 atmosphere, not only a part of stable organic sulfurs can be decomposed, but also more stable organic sulfurcontaining structure can be broken down into less stable one. Syngas and 1% O2-N2 atmospheres have almost the same effect as hydrogen on sulfur transformation at 700 ℃.