The invention relates to a venturi type desulfurizing device adopting a 
spray drying method and a desulfurizing method of the desulfurizing device. A vertical cylindrical 
tower-shaped structure is adopted, a venturi 
throat is arranged in the middle of a 
tower body, and 
flue gas enters a shell through an upper air inlet and passes through a desulfurizing 
tower from top to bottom. SO2 in the high-temperature 
flue gas and a reactant sprayed in through a 
nozzle are subjected to a 
chemical reaction, a reaction 
side product is 
solid Na2SO3 
powder, most of the 
solid Na2SO3 
powder falls into a lower ash bucket, and the rest of the 
solid Na2SO3 
powder is discharged out of the tower body from a lower air outlet of the tower body along with the desulfurized 
flue gas, enters a subsequent dust removing process and is collected. The PH value of the solid desulfurizing 
side product is neutral or alkaline, no 
wastewater is generated in the whole desulfurizing process, and the temperature of the 
flue gas at an outlet of the desulfurizing tower is higher than the 
dew point temperature by 15 DEG C or above all the time. The problems that in a traditional desulfurizing technology, 
flue gas is not distributed uniformly in a flow field of a desulfurizing tower, full mixing of a desulfurizing agent and the 
flue gas is not uniform, 
mushroom heads and hair hanging are likely to be formed at a 
nozzle by a reactant and a reaction 
side product, and consequently running stability is influenced are solved.