The invention relates to a dual 
flue gas purification technology and a purification 
system thereof in the field of wet 
flue gas purification. The technology comprises primary wet purification and secondary adsorbing purification, wherein a clean 
flue gas obtained after raw 
flue gas is primarily purified enters a clean 
flue gas channel, and the clean 
flue gas obtained after the primary wet purification is processed by secondary adsorbing purification. The 
system comprises a primary wet purification device and a secondary adsorbing purification device, wherein the primary wet purification device comprises a raw flue gas channel, an adsorption 
tower and a clean flue gas channel which are sequentially connected with one another; the secondary adsorbing purification device is respectively connected with the clean flue gas channel and the adsorption 
tower. The technology disclosed by the invention is based on an optimized design, and stable in 
system operation, pollutants such as gas liquid 
slurry materials, dust, 
aerosol and the like mixed in the clean flue gas can be effectively controlled, especially, the substances such as sulphurous acid 
nitrite and the like forming particulate matters (PM)2.5 can be effectively prevented from entering the 
atmosphere, the 
environmental effect is significantly enhanced, secondary 
pollution of the clean flue gas to the 
atmosphere caused is effectively prevented, and the dual flue gas purification technology and purification system thereof are applicable to popularization and application in the field of flue gas purification.