Selective catalytic reduction denitration system

The utility model discloses a selective catalytic reduction denitration system which comprises a smoke inlet channel and a selective catalytic reduction denitration device, wherein one or more ultrasonic generators are arranged in the smoke inlet channel; the aqueous ammonia inlets of the ultrasonic generators are communicated with an aqueous ammonia source through an aqueous ammonia pump; aqueous ammonia atomization holes in the ultrasonic generators are positioned in the smoke inlet channel. The selective catalytic reduction denitration system and method have the advantages that according to an ultrasonic atomization method, electronic high-frequency oscillation and high-frequency resonance of an atomization flake are utilized for scattering of an aqueous ammonia molecular structure, so as to generate natural and flowing water mist without heating or adding of any chemical reagents, that is, ammonia gas can be generated and completely mixed with smoke without heat energy consumption.