Abstract: Wujiaping coal pyrolysis was investigated in a fluidized bed reactor under atmospheres of 3.0%, 5.6% and 8.7% O2N2 at the temperatures ranging from 500℃ to 800℃ and the residence time of 30min. GC and flue gas analyzer were used to measure the sulfurcontaining gases . It is found that the main forms of sulfurcontaining gases are H2S, COS and SO2, which have similar evolution rule: the evolution rate increases quickly with increasing temperature and oxygen content. The ratio of H2S and COS to the total sulfur amount in pyrolysis gas decreases much under 5.6% O2N2 compared with that under 3.0% O2N2, however, under 8.7% O2N2, it increases greatly. But the effect of oxygen content on SO2 evolution is contrary to that of H2S and COS. Under 5.6% O2N2, above 93% of total sulfur in the pyrolysis gas is SO2, but under 8.7% O2N2 the ratio decreases remarkably to 56%. This suggests that under 8.7% O2N2, more oxygen takes part in the reactions of C—C bonds cleavage, which results in the formation of more CO and higher ratio of CO/SO2 than that under 5.6% O2N2.