Abstract: In order to obtain fly ash with high desulfurization activity, in combination with scanning electron microscope(SEM),particle size analyzer, X-ray diffractometer(XRD),X-ray photoelectron spectrometer(XPS),chemical titration and other characterization methods, the dropper tube furnace was used to study the phase morphology, chemical components of fly ash and active CaO content obtained from pulverized coal combustion with different combustion temperatures. The influence law of coal combustion temperature on the characteristics of fly ash was investigated. The results showed that the combustion temperature had significantly affected on the phase morphology of fly ash, chemical composition, sulfur fixation rate and the content of active calcium oxide. With the temperature increased, the number of irregular shape particles gradually decreased, and particle size increased, the contents of CaO and Ca(OH)2 increased, the content of SO2 showed a trend of rise before they were gentle, the content of active calcium oxide increased gradually, which could effectively improve the fly ash as desulfurizer desulfurization of potential. By comprehensive analysis, the temperature about 800 ℃ was the best combustion conditions.