Depending on the desulfurization reaction tempetature, desulfurization ash generated at high temperature furnace zone is simulated by adding different weight percentage of CaSO4·2H2O to the ordinary fly ash, at the same time calcining at 900℃.And then by the experiment of workability and strength, the effect of gypsum content in furnace desulfurization ash on material properties and the pretreatment method are studied.The results show that: compared with ordinary fly ash, the desulfurization ash can improve workability, but it is obvious for its enhancement but only the gypsum content exceed 10% by mass.Secondly, desulfurization ash can decrease strength.Thirdly, as for pretreatment method, if the gypsum content in desulfurization ash is less than 10%, pretreatment method can improve the fluidity, however, exceed 10%, this method reduce the fluidity, even lower than the control specimens.And this method can increase the compressive and flexural strength, especially 28days strength.