Abstract: Sulfur-containing flue gas emission from coal-fired industrial boilers is one of the main sources of atmospheric pollution. With the increasingly stringent requirements for different pollutants emission from boiler flue gas,the state has implemented the ultra-low emission standard for flue gas,the requirement for SO2 to be below 35 mg/m3,so the control of SO2 in boiler flue gas is imminent. In this paper,the characteristics of wet and semi-dry desulturization technologies were analyzed,the differences,advantages and disadvantages of different wet desulfurization technologies were compared,the limestone-gypsum method and NO Gap Desulfurization processes and desulfurization mechanism were elaborated in detail,and the feasibility and economy of the two desulfurization technologies were analyzed and compared. At present,the desulfurization efficiency of limestone-gypsum process is 95%. The limestone forced oxidation system is widely used. The scaling,blocking,corrosion and waste water are the main problems of this technology. The NGD desulfurization technology uses fly ash as desulfurizers. Due to the particularity of coal in Shendong area,there are more active substances in fly ash. Under the condition of water,the Si and Al in fly ash dissolve and hydrate with hydrated lime. The high hydrate produced greatly improves the desulfurization efficiency. The desulfurization efficiency is between 80% and 90%. The economy of NGD desulfurization technology is better than limestone-gypsum method,and the characteristics of coal-fired industrial boilers are different from those of power plant boilers. For medium and small coal-fired boilers,the NGD desulfurization technology has good adaptability and development prospects.