Based on the heterogeneous characteristics of rock at mesoscopic level

the thermal-stress-damage coupled action during the failure process of rock subjected to thermal stress is described with elastic damage mechanics and thermal-elastic theory. A mesoscopic thermal-mechanical-damage coupling model

implemented in rock failure process system

RFPA2D

is proposed. The RFPA2D is used to simulate the stress distribution and failure patterns in homogeneous and heterogeneous specimen subjected to thermal loading. The numerical results coincide well with the corresponding mathematic resolution and experimental results; so it is proved that the proposed model as well as the numerical system （RFPA2D） are reasonable and effective in investigating the failure of heterogeneous materials under thermal stress.