Abstarct: In this thesis, an isotropic medium with static cracks under heat shock has been studied. In this research, the dynamic thermoelasticity equations of the coupling have been used considering Chandrasakharia-Tizo theory. Using the extended finite element method, the equations are discretized in dimensionless space. Interaction integral has been used to calculate the stress intensity factors. Finally, some examples are obtained using the numerical method and the distribution of temperature, displacement, Stress in the direction of the X and Y axes along a homogeneous laxyer. Also, stress intensity factors under temperature shock have been investigated and compared with classical thermoelasticity theory. The results show that, the speed of temperature, displacement and stress waves are limited according to Chandrasakharia-Tizo theory, contrary to the classical thermoelasticity theory. Also, the maximum values of displacement and stress according to Chandrasakharia-Tizo theory occur at a shorter distance from the wall under heat shock, and the maximum stress intensity factor of mode I and - in asymmetric loads - the stress intensity factor of mode II according to the classical thermoelasticity theory is greater than the Chandrasakharia-Tizo theory and occurs earlier.