In order to explore the influence of fault tectonism on the characteristics of the chemical structure of coal and the characteristics of the microcrystalline structure. The primary coal and fault tectonic coal of the Hongqingliang mine and Duanwang mine were analyzed by Fourier Transform Infrared Spectroscopy FTIR and X-ray diffraction XRD. The following results showed that because of the influence of fault tectonism, the contents of benzene ring disubstituted and benzene ring tetrasubstitution in Hongqingliang and Duanwang fault tectonic of coal were significantly higher than those in primary coal, the contents of benzene ring trisubstitution and benzene ring pentasubstitution were lower than those in primary coal, and the contents of ether bond C-O-C stretching vibration, methylene -CH2 antisymmetric bending vibration, both methyl, methylene and aromatic ring substituted by hydroxyl -CH3 and -CH2 in fault tectonic of coal were higher than those in primary coal. In comparison, the contents of the polar bond of ether vibration, carbon-carbon double bond, methine and phenol of aromatic hydrocarbon in fault tectonic of coal were lower than those in primary coal. The aromaticity fa of fault tectonic of coal in Hongqingliang and Duanwang mine was 1.01 and 1.03 times that of primary coal, the aromatic cyclocondensation DOC was 1.01 and 3.7 times that of primary coal, the ratio of CH2 to CH3 was 0.933 and 0.94 times that of primary coal, and the aromaticity I was 1.01 and 1.34 times that of primary coal, respectively. The conclusions showed that fault tectonism influenced promoting the shedding of functional groups and fat chains, increasing the degree of polycondensation of coal, reducing the length of fat side chains in coal and increasing the content of aromatic structure. The XRD test results showed that the primary coal and the fault tectonic coal had similar mineral components, and the fault tectonism did not significantly change the types of mineral components in coal. There was a (002) characteristic band near the diffraction angle 2θ=26°, which indicated the presence of a small amount of layered graphite structure, while there was no displayed zone, which indicated the basal low growth level of graphite structure in coal. Compared with the primary coal, the value of the variation range of intergranular spacing d002 of the fault tectonic of coal in Hongqingliang and Duanwang mine was very small. The value of the microcrystalline stacking height Lc was 0.904 5 times and 0.902 7 times of the primary coal respectively, the value of the aromaticity fa-XRD was 1.143 9 times and 1.066 9 times of the primary coal respectively, and the value of the average layer Nave of the crystal stacking was 0.909 45 times and 0.923 56 times of the primary coal respectively. Because of the fault tectonism, the stacking degree of aromatic lamellae of coal reduced, the aromaticity of coal increased, and the stacking layers of coal microcrystalline structural units reduced, indicating that the fault tectonism promoted the transformation from non-aromatic compounds to aromatic compounds in coal. The aromaticity and maturity of the fault tectonic coal were higher, but the combustion reactivity of fault tectonic coal was weaker than that of primary coal.