The EXPEC 2000 FT continuous monitoring system for flue gas emissions adopts an in-situ extraction and full process high-temperature tracing method (hot wet method) to extract flue gas into the system for analysis. Among them, the concentration of gaseous pollutants and humidity is inverted using Fourier transform infrared technology principle, which utilizes the characteristic absorption of gas molecules in the infrared spectrum. The beam emitted by the infrared light source forms an interference spectrum through an interferometer, which is focused on the detector after being absorbed by the characteristics of the sample gas in the measurement cell. After data processing, a single channel spectrum is obtained, and the concentration values of various gas parameters are finally calculated through an algorithm model. Zirconia is used for oxygen (O2) measurement, platinum resistance method is used for temperature (T) measurement, pressure sensor method is used for pressure (P) measurement, and S-shaped pitot tube method is used for flow rate (F) measurement.