The invention discloses a falling film washing 
system realizing ultralow emission of 
coal-fired power 
plant desulfurated 
tail gas and a technology thereof. The washing 
system comprises an absorbing section, an automatic circulation suction liquid bath, a special plate group 
demister matched with the absorbing section and a falling film washing section matched with the special plate group 
demister. The washing technology includes the steps that 1, 
flue gas enters the absorbing section and then makes contact with an absorbent; 2, most liquid drops with the 
large particle size and 
smoke dust in the 
flue gas are removed by the automatic circulation suction liquid bath to obtain new 
flue gas, then the 
flue gas is input into the absorbing section again; 3, the 
flue gas is conveyed to the special plate group 
demister through the absorbing section, and liquid drops with the 
diameter being 10 micrometers or above in the 
flue gas are removed by the special plate group demister; 4, impurities continue to be removed by the falling film washing section. Top space of an existing desulfuration 
tower and site space are fully used, separation efficiency and accuracy are improved, and the content of particulate matter in the wet desulfurization 
tail gas is reduced to the ultralow emission level.