The invention discloses a high efficiency wet-type desulfurization method through 
ammonia recovery method for oxidation and concentration outside a 
tower, and a device thereof. The method comprises the following steps: (1) feeding 
flue gas into the top part of a concentrating 
tower after dust removal, 
cooling down and humidifying the 
flue gas, then feeding the 
flue gas into a first level venturi section of a desulfurization absorption 
system to contact atomized 
ammonia water so as to have the first level absorption reaction, performing the second level and the third level desulfurizations, and discharging the 
flue gas after the purification; (2) oxidizing the 
ammonium sulfite solution generated in a desulfurizing 
tower and then overflowing the 
ammonium sulfite solution into a 
mother liquor tank from the top part of an oxidation tank; and (3) pumping the 
ammonium sulfate solution in the 
mother liquor tank to the top part of the concentrating tower through a 
mother liquor pump to perform heat exchange with the high temperature 
flue gas after atomization so as to form a supersaturated solution containing 3 to 5 percent of 
crystal, wherein the supersaturated solution flows out of the bottom of the concentrating tower and is pumped into a hydraulic 
cyclone through a 
slurry pump to perform the first level 
solid-liquid separation, and then the clear solution automatically flows into the mother liquor tank; the 
crystal-liquid 
mixed solution flowing out of the bottom of the concentrating tower automatically flows into a centrifugal 
machine to perform the second level 
solid-liquid separation, and then the clear solution automatically flows into the mother liquor tank; and 
solid ammonia sulfate is fed into an automatic 
packaging machine to be packaged and put into storage. The method has simple processes, greatly reduces investment, and can reclaim agricultural level ammonia 
sulfate and industrial level ammonia sulfate.