Abstarct: In this paper, the stress intensity factors (SIFs) are computed for a stationary crack in an isotropic 2D finite domain under thermal shock using the eXtended Finite Element Method (XFEM) and the interaction integral method. The fully coupled generalized thermoelasticity theory baxsed on Green- Lindsay (G-L) model is considered. An interaction integral is developed to compute the stress intensity factors in which the dissipated part of the strain energy density is accounted to preserve domain-independency of. The Newmark time integration scheme is used to solve semidiscrete governing equations. In several numerical examples, the effect of stress and heat waves on the SIFs as well as the heat wave on the temperature distribution baxsed on the G-L model is studied deeply. According to the results, the speed of stress and temperature waves controls the trend of stress intensity factors especially at early time of the thermal shock. When the mechanical stress wave reaches to the crack tip, the thermomechanical SIFs begins greater than thermal SIFs. Moreover, the effect of the mechanical stress wave on the SIFs in G-L model is more evident.