The depletion of conventional oil and gas resources has intensified the need for unconventional alternatives, such as continental shale oil and gas. In-situ heating technology offers a promising pathway to enhance reservoir permeability by inducing thermal fracture networks. However, the mechanical response of bedded shale to thermal loading remains poorly understood, hindering its field application. This study integrates laboratory experiments with discrete element method (PFC2D) simulations to investigate the thermally induced evolution of microfractures, failure modes, and mechanical properties of shale from the Lucaogou Formation, Junggar Basin. The results reveal distinct temperature thresholds and structural dependencies. Porosity and permeability increase in stages, with a sharp rise above 500?℃. Acoustic wave velocity drops by approximately 50% from room temperature to 800?℃, while the attenuation coefficient increases nearly fivefold. Uniaxial compressive strength and elastic modulus deteriorate rapidly above 300?℃, driven by the initiation and propagation of thermally induced microcracks. Bedding density amplifies thermal damage: higher density promotes microcrack growth, reduces strength and modulus, and shifts failure toward bedding-plane dominance. The effect of bedding angle is non-monotonic—failure is controlled by through-bedding or shear at low (0°) and high (90°) angles, but transitions to bedding-plane dominated failure at intermediate angles, where microcrack density and mechanical degradation reach their maxima. From a thermal–structural coupling perspective, this study elucidates the co-evolution of physical, acoustic, and mechanical behaviors in bedded shale under thermal treatment. The consistency between experimental and numerical results provides mechanistic insights and supports the feasibility of in-situ heating for efficient development of continental shale oil in China.