Abstract: Based on the heterogeneous characteristics of rock atmesoscopic level, the thermal-mechanical coupled behavior during the failureprocess of rock subjected to thermal stress is analyzed with elastic damagemechanics and thermal-elastic theory. A mesoscopic thermal-mechanical (TMModel) coupling model, implemented in RFPA, is proposed, which can beused to study the damage and failure process, as well aselastici stresses for the coupled thermo-mechanical rock problem. With thenumerical model, the damage and associated mechanical property evolutionof mesoscopic structure in rocks subjected to TM loading can beanalyzed.Numerical simulation is carried out to investigate the stability of the rockpillar in a Hard Rock Laboratory. The numerically obtained stress field,failure pattern of pillar rock and associated AE events all agree wellwith the in-situ data, which shows that the proposed model isreasonable and effective, and may provide guides for theexperiment design and associated applications.