<p>Underground engineering is gradually exploring deeper, which puts forward new requirements for hard rock breaking technology. Microwave-liquid nitrogen (LN₂) cooperative assisted rock breaking technology is considered an efficient rock breaking method that can cause a strong thermal shock effect on the rock mass, effectively reduce drill bit wear and improve drilling efficiency in hard rock formations. Therefore, the structural damage and tensile failure properties of the granite under combined microwave and LN₂ are investigated experimentally. The results show that with the increase of the microwave time and thermal shock cycles, the internal structure damage of the granite increases significantly, and the initiation stress, tensile strength, and splitting modulus of the granite decrease. With the deepening of the thermal shock cycle, the number of microcracks in the granite increases and transgranular cracks appear gradually. After 16&#xa0;min of microwave irradiation at a power of 0.9&#xa0;kW, the tensile strength and splitting modulus of the granite decreased by 51.8% and 60.1%, respectively. In comparison, following 20 thermal shock cycles, these two mechanical parameters of the granite exhibited more significant reductions, with decreases of 58.6% and 69.7% correspondingly. The microwave-LN₂ treatment can effectively reduce the energy required for mechanical failure of the granite and increase the number of crack propagations. The shear crack proportion and induced crack surface complexity increase with the increase of the microwave time and thermal shock cycles. A thermal-mechanical model with continuous-discrete coupling is established to simulate and reveal the cracking mechanism of the granite under the microwave-LN₂. The research results provide a new idea for increasing speed and reducing cost in deep hard formation drilling.</p>