Self-adaptive differential absorption spectrum measuring method of concentration of flue gas pollutants and device

The invention discloses a self-adaptive differential absorption spectrum measuring method of concentration of flue gas pollutants and a device. The method comprises the following steps: using empirical mode decomposition (EMD) to combine a 3 sigma criterion to determine decomposition scale and threshold value of gaseous pollutants absorbance, fully remaining own non-stationary characteristics of differential absorbance, effectively reducing background spectrum interference caused by dusts, establishing equation sets about concentration C1, C2 until Cn of gaseous pollutants to n types of pollutant gases (SO2, NOx) to be measured according to the differential absorbance after reducing noise and eliminating trend terms, and adopting a linear least square algorithm to obtain the concentration of the gaseous pollutants to be measured. The self-adaptive differential absorption spectrum measuring device of concentration of flue gas pollutants comprises a light source, an optical fiber coupler, an optical fiber spectrometer, a computer and an optical system consisting of a collimating lens, a beam splitter, a reference beam lens, a reflecting lens, a converging lens, a light baffle, an optical fiber coupler, a cross reticle, a sighting eyepiece, a lassenite window and an angle reflecting lens.