To study the influence of crack inclination angle on the mechanical properties and the energy evolution mechanism during the rock failure, a calculation model was constructed based on the particle flow dispersion element numerical platform, and uniaxial compression numerical experiments were conducted on rock samples with different crack inclination angles. The research results indicate that as the crack inclination angle increases, the peak strength and elastic modulus of fractured rocks show a “V” shaped trend of first decreasing and then increasing. When the crack inclination angle is small, the rock sample mainly undergoes shear failure and vertical splitting failure, and the number of tensile and shear cracks mainly increases in a stepped pattern. The larger the crack inclination angle, the more the rock failure mode will transition to a mixture of vertical splitting and shear failure, and the curve of the number of tensile and shear cracks will increase exponentially. As the crack inclination angle increases, the total input energy and elastic strain energy of the rock sample show a trend of first decreasing and then increasing. The larger the crack inclination angle, the faster the increase in dissipated energy, but the lower the final dissipated energy when the rock sample fails. The existence of cracks significantly weakens the energy storage limit, weakens the ability of the rock to absorb and store elastic strain energy, and enhances its energy dissipation ability at peak stress in the rock specimen during compressive failure.