In order to study the effectiveness of the mesoscopic model, a mesoscopic continuous-discontinuous coupling model of coal gangue concrete circular-columns confined by glass fiber reinforced composite (GFRP) sheet was established by three-dimensional PFC-FLAC coupling method. The validity of the model was verified by experimental data. On this basis, the effects of 0, 2 and 4 layers of GFRP sheet on the axial compression performance, failure mode and energy absorption characteristics of coal gangue concrete circular-columns were studied. The results show that the established mesoscopic model has high accuracy. The ultimate failure strength of coal gangue concrete circular-columns increases with the increase of GFRP sheet layers. The energy absorption efficiency and volume specific energy absorption also increase with the increase of GFRP layers, but the proportion of increase decreases. The ductility characteristics of stress-strain curves, peak strength, failure mode, total energy density change, energy absorption efficiency and volume specific energy absorption of coal gangue concrete circular-columns are considered comprehensively, and the increasing layers can enhance the axial compression performance of the coal gangue concrete circular-columns, taking into account the principles of economic cost and winding level.