Fourier transform infrared (FTIR) spectra of coal dust and its explosion solid residues were studied. Coal dust explosion test was carried out on a 20-L explosion device, and the variation of different functional groups and FTIR structural parameters of pre- and post-explosion dust were semi-quantitatively analyzed by deconvolution of the FTIR spectra. In addition, the relationship of explosion pressure (P-m) and pressure rise rate ((dP/dt)(m)) with functional groups was investigated. The results show that the largest consumption of functional groups in coal dust explosion process is distributed in 1800-1000 cm(-1) band, and most of the ether oxygen bond, methyl and benzene ring are removed from the coal macromolecule. The improved condensation degree of coal macromolecular aromatic ring and the decreased aliphatic side chains lead to a more compact coal molecular structure. The consumption of functional groups during coal dust explosion is positively correlated with the P-m and (dP/dt)(m). The research provides a new feasible method for the evaluation of the organic dust explosion risk by its functional group. Moreover, it can be used effectively as basis for suppressing the organic dust explosion. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.