Abstract: To reveal the anisotropic mechanical properties and failure mechanisms of deeply buried layered shale, a study was conducted on the Silurian shale section of the Siiping-Niutoushan duplex in the the Yangtze-Han water diversion project. The MTS rock mechanics test system was used to conduct uniaxial compression and triaxial compression tests. Combined with the observation of the microscopic characteristics of the fracture surface by scanning electron microscopy, the influence laws of bedding dip angle and confining pressure on the mechanical parameters and failure mode of shale were analyzed. The results showed that the peak strength of shale presented a "U" shape distribution with the bedding dip angle β, with the maximum value occurring at β=0° and the minimum value concentrated in the range of β=40°-55°; increasing the confining pressure could enhance the elastic modulus and weaken the anisotropy of strength. Among them, the anisotropy degree of compressive strength decreased continuously with the increase of confining pressure, and the anisotropy degree of elastic modulus stabilized after the confining pressure exceeded 5 MPa. The failure mode was jointly regulated by the bedding dip angle and confining pressure. Under uniaxial compression, it was mainly shear along the bedding, and under high confining pressure, it transformed into a "shear along bedding+transverse bedding tension" composite mode. The internal friction angle and cohesion also presented a "U" shape distribution, reaching the minimum value in the range of β=45°-55°. This study clarified the key influencing factors and evolution laws of the mechanical properties of layered shale, providing a reliable experimental basis for the prediction of deformation and failure of surrounding rock in deep-buried layered shale tunnels and the optimization of support schemes.