The invention relates to the technical field of 
selective catalytic reduction denitrification of industrial 
flue gas, in particular to a 
zoning-regulating double-layer 
ammonia injection grid applied to a 
selective catalytic reduction denitrification device for industrial 
flue gas. In order to solve the problems that the 
ammonia distribution on a 
flue section of the conventional 
ammonia injection grid is quite non-uniform, which affects the denitrifying efficiency and increases the 
escape rate of ammonia, and the like, the 
zoning-regulating double-layer ammonia injection grid applied to the 
selective catalytic reduction denitrification device for the industrial 
flue gas divides the flue section into two equal subzones; the ammonia injection function of one subzone (1 / 2 of the flue section area) is realized by an upper ammonia injection grid and the ammonia injection function of the other subzone is realized by a lower ammonia injection grid; and according to the distribution rules of the flow rates of the 
flue gas in the two flue section subzones and different concentrations of 
NOx in the 
flue gas, the ammonia injection amount of each subzone is regulated and controlled by an ammonia injection regulating valve, so that the ammonia injection amount is adjustable on different zones of the flue section, the uniform 
mixing effect of the ammonia and 
nitrogen oxides in the flue gas is optimized, the denitrifying efficiency is improved, and the 
escape rate of the ammonia is effectively reduced. The uniform 
zoning-regulating double-layer ammonia injection grid applied to a selective catalytic reduction denitrification device for industrial flue gas has a good uniform 
mixing effect of the 
nitrogen oxides in the flue gas and the ammonia, improves the denitrifying efficiency, effectively reduces the 
escape rate of the ammonia, and is applicable to 
NOx selective catalytic reduction denitrification devices in 
coal burning, 
metallurgy, 
chemical industry and other industries.