Abstract: By using liquid nitrogen (LN2) fracturing to create a massive network of fractures in the reservoir, the thermal energy extraction efficiency of hot dry rock reservoirs can be effectively improved. To investigate the effects of LN2 cold shock treatment on the fracturing mechanism and fracture effects of reservoirs at different temperatures, this study conducted uniaxial compression tests on granite samples that had undergone high-temperature heating (25℃-400℃) and liquid nitrogen cold shock treatment. The evolution characteristics of the mechanical strength and acoustic emission parameters of granite were analyzed, and a granite acoustic emission damage constitutive model was further constructed to evaluate and predict the deformation and strength characteristics of granite after high-temperature heating and liquid nitrogen cold shock treatment. And further, a damage constitutive model for granite acoustic emission was constructed to evaluate and predict the deformation and strength characteristics of granite after high-temperature heating and LN2 cold shock treatment. The results indicate that the combined effects of high-temperature heating and LN2 cold shock significantly degraded the mechanical properties of granite, with a gradual decrease in peak strength and a maximum reduction of 32.8%. Meanwhile, with the increase in heating temperature, there were differences in thermal expansion deformation between different mineral particles, resulting in a lack of coordination in deformation between mineral particles. With the increase in initial heating temperature, the average maximum b-value of acoustic emission significantly increased, with a maximum increase of 32.2%, and the strain corresponding to the initial silent stage of acoustic emission ringing counts decreased significantly, with a maximum reduction of 54.3%. With the increase in heating temperature, the LN2 cold shock treatment caused the microcracks to grow more densely. Under external loading, the microcracks continuously expanded and penetrated, making it easier for the granite to undergo shear deformation and for the initial stress level of shear failure to gradually decrease, with a maximum reduction of 62.3%. Meanwhile, the proportion of RA-AF scatter plot values in the shear zone increased, with a maximum increase of 29.5%. Additionally, this study constructs an acoustic emission constitutive model using accumulated ringing counts as a variable, which can describe the evolution characteristics of different mechanical parameters of granite during the deformation and failure process after high-temperature heating and LN2 cold shock treatment.