Abstract: Thick-hard roofs, characterized by high strength and good integrity, are widely distributed in the coal measure strata in the northwest energy base. Conventional hydraulic fracturing has the problems of high initiation pressure, limited fracture propagation, and difficult control of weakening range. Considering these problems, this paper proposed a synergistic weakening method that integrates liquid nitrogen jet pre-cooling with subsequent pressurized fracturing. Through physical simulation tests and thermal-fluid-solid-damage multi-field coupling numerical simulations, the mechanical response, damage evolution, and weakening zone expansion law at the end of pre-cooling were analyzed under different pre-cooling pressure and time conditions. The results show that liquid nitrogen jet pre-cooling can weaken the pressure-bearing capacity of the specimen in the subsequent pressurized fracturing stage. With the extension of pre-cooling time and the increase of pre-cooling pressure, the peak pressure is reduced by 19.1% and the peak time is shortened by 31.0%. The acoustic emission (AE) response characteristics show that the micro-crack activity and energy release have occurred in the pre-cooling stage, and the AE count and energy ratio move forward to the pre-cooling stage. Besides, the overall b-value decreases with the extension of the pre-cooling time, indicating that the crack activity gradually shifts from scattered micro-crack initiation to large-scale and localized propagation. The numerical simulation results show that the low-temperature affected zone and the damage zone are first formed near the injection hole and then expand radially. Raising the pre-cooling pressure will promote the advancement of the distal dominant crack front. At 1500 s, compared with the 1 MPa case, the damage area ratio and R_eq under 2 MPa increase by 5.8% and 2.8%, whereas R₉₅ and R_max increase by 17.5% and 8.5%, respectively, which suggests that higher pre-cooling pressure mainly enhances the outward extension of cracks. Liquid nitrogen jet pre-cooling changes the subsequent pressurized fracturing process from crack initiation in an intact specimen to propagation and coalescence along the pre-damaged zone, thereby reducing the threshold for subsequent pressurized fracturing. This study provides a theoretical reference for efficient permeability enhancement and fine control of thick-hard roofs in coal measure strata.