Abstract: In order to study the effect of air staged combustion on the properties of fly ash, the air volume ratio of highdesulfurization active fly ash was obtained.In this paper, the dropper tube furnace was used.Combined with SEM, particle size analysis, XRD, XPS, plasma and chemical titration test equipment and methods, the properties and activities of fly ash obtained from pulverized coal combustion with different secondary air volumes and different proportions of sulfur-fixing agent were investigated.The results show that the effect of air staged combustion on physical morphology of fly ash is not significant, but the chemical composition, sulfur fixation rate and the content of activited calcium oxide change significantly.With the increase of secondary air volume, the content of Ca (OH) ₂ increased after decreased first, but CaO presents adversely, SO₂ concentration first increased and then decreased, the content of activited calcium oxide reduced first increases, the burning rate and ratio of active calcium oxide content in fly ash hit the highest when the secondary air volume is about 95%, which is respectively about 45% and 17%; the breakthrough time and the cu-mulative desulfurization rate all showed a downward trend and then a rising trend with the increase of the secondary air volume, when the secondary air volume is 95%, fly ash desulfurization performance is best.