Abstract: Coal-fired power plants remove SO2 using wet limestone-gypsum or ammonia desulfurization，and using spray lye to absorb SO2 in flue gas． After desulfurization tail gas contains a large amount of calcium salt or ammonium salt of solid and liquid particles，these tiny particles aerosol with smoke into the atmosphere from chimney，become the important part of dust-haze， which is one of the main causes of PM2. 5 pollution． This paper introduces the principle，process flow，technical features of JTECH ammonia desulphurization and wet electrostatic precipitator technology，and expounds the technology of the key breakthrough on the traditional ammonia desulphurization technology． It is verified by use that the actual operation desulfurization efficiency is more than 98%，the particulate matter concentration at outlet is less than 20 mg /m3，the ammonia escape is below 5 mg /m3，and no amnonium carried by flue gas at the outlet of stack． The technology reaches the expected target．