<p>In order to study the evolution of fracture characteristic parameters during the failure of structural coal assemblage under uniaxial compression. NanoVoxel-3000 geotechnical multi-scale high-resolution comprehensive scanning and analysis system was used to conduct uniaxial compression experiments of coal composite specimens containing structures, and CT scanning was used to obtain CT data under different loads CT data under different loads were obtained. Combined with 3D visualization software Avizo, the fracture distribution characteristics of structural coal assemblage specimens during the failure process were studied. The characteristic parameters of crack, including crack volume, crack surface area, crack number, crack rate and crack density, were analyzed statistically. The spatial distribution patterns of structural coal assemblage with changing characteristic parameters were obtained. The results shown that the main crack length, crack volume, crack surface area, crack number, crack rate and crack density all increased linearly with the load. The changes were relatively gentle in the compaction stage and elastic stage. Plastic stage and failure stage changed rapidly. When the load pressure was 12&#xa0;MPa, the deflection rate of the upper interface angle reached a maximum of 81.73%. When the load pressure was 16&#xa0;MPa, the deflection rate of lower interface angle was 1.75%. In the elastic stage, compared with the other three stages, the fracture evolution rate, evolution rate, fracture density and fracture rate of structural coal assemblages had sudden changes, increasing to 16.91%, 2.80 × 10⁻⁴&#xa0;cm/s, 106.40% and 106.40%, respectively. With the increase of load, the number of cracks changed from 0.01 mm³ ≤ V &lt; 0.05 mm³ to 0.1 mm³ ≤ V &lt; 0.5 mm³. The fracture volume of V ≥ 5 mm³ increased to 942.52 mm³, accounting for 93% of the total fracture volume. The fracture surface area was 21,430.44 mm². The above research results could provide theoretical support for coal and gas outburst.</p>