Abstract: With the development of deep engineering in China， the evolution law and formation mechanism of fault stick-slip instability process in the deep area and high rock temperature need to be studied. Therefore， a numerical thermo-mechanical coupling model is constructed with discrete element code， the mechanical behavior of fault stick-slip under six different temperature fields was studied in detail， and the influence mechanism of different temperature fields on the process of fault stick-slip instability was explored. The results show that the failure patterns and failure modes of fault stick-slip change with the increase of temperature. The number of stick slip， initiation slip stress and initiation slip stress drop show an overall decreasing trend with increasing temperature. The energy dissipation of fault stick-slip is dominated by frictional sliding. When the fault starts sliding， the total strain energy is positively correlated with temperature， and the dissipated energy is negatively correlated with temperature.

Key words: fault stick-slip； temperature fields； discrete elements； fracture evolution