Acetonitrile, widely used in pharmaceutical and chemical industries, is a flammable and explosive chemical which can cause fire accidents with great harm. It is of great practical value to explore the fire pollution characteristics of acetonitrile combustion by studying its temperature and concentration fields and flame radiation spectra. In this paper, the spatial concentration values of NO, a product of acetonitrile pool fire, at the 20, 40, 60, and 80 s on a 5 cm-diameter scale were obtained using Planar Laser Induced Fluorescence (PLIF) and Fluent numerical simulation methods, and the temperature and concentration fields of acetonitrile combustion at different times were obtained by combining CFD and FDS simulations. Secondly, data from the temperature field and concentration field of the acetonitrile flame (the flame was divided into six thermodynamic equilibrium regions) were used to construct an acetonitrile flame spectral radiation model based on absorption coefficients of high-temperature gas molecules and overall radiative transfer equation of the flame in HITRAN database. Again, data from the concentration field and temperature field of the acetonitrile flame were substituted into the flame spectral radiation model, and the model simulation results were compared with the measured acetonitrile flame spectral data under the same conditions to verify the model accuracy and compare with the Radcal model. Finally, the concentration inversion of NO, a characteristic pollution product of combustion, was performed using the self-built flame spectral radiation model. The results showed that: (1) the flame temperature range of 5 cm-diameter acetonitrile pool fires was 400～1 000 K, and the temperature was higher in the region of 60～80 mm above the pool fire with the highest temperature of 945 K; (2) the volume fractions of combustion products of 5 cm-diameter acetonitrile pool fire at 20, 40, 60 and 80 s moments were 0.005%～0.025 5% for NO, 0.034 5%～0.062 5% for H2O, and 0.055 5%～0.085 5% for CO2; (3) an acetonitrile flame spectral radiation model was built by ourselves, and comparison between the model simulation value and the actual measured value showed that: in combustion products, the CO2 characteristic peak accuracy was 86.8% min and 88.7% max; NO was 79.6% min and 84.9% max; and H2O was 84.6% min and 89.1% max. Compared with spectral radiation values calculated by the Radcal model, the calculation accuracy of our model was improved by about 10%; (4) the inversion accuracy of the concentration of NO, the characteristic product of acetonitrile combustion, in dominant band of 5.62～5.66 μm at moments of the 20, 40, 60, and 80 s was 76.9%, 78.5%, 94.7%, and 81.3%, respectively. This study can provide a basis and reference for detecting combustion field information of large-scale acetonitrile chemical fires and the quantitative inversion of combustion pollution product concentrations by remote sensing.