<p>In cold regions, rock mass is often prone to slip-type disasters along structural planes, resulting in severe casualties and economic losses. This paper is aimed at revealing the shear failure mechanism of structural planes under the influence of freeze–thaw cycles and shear loading and developing a corresponding shear strength model. First, through drying and saturation treatments and freeze–thaw cycle test, the degradation patterns of the internal structure and pore characteristics of rock samples are explored from aspects such as damage images, P-wave velocity, nuclear magnetic resonance (NMR) images and morphological parameters. Second, uniaxial compression, Brazilian splitting, triaxial compression and direct shear tests are conducted to investigate the deformation, failure and strength characteristics of rock samples under the combined influence of freeze–thaw cycles and loading. Third, 3D laser scanning is performed on structural planes, and a survival function of the Weibull distribution is adopted to develop a critical apparent dip angle–potential contact area quantification model. A single key parameter, characteristic angle, is applied to measure the morphological characteristics of structural planes. A shear strength model of structural planes is built based on the failure mechanism of structural plane samples under compressive-shear loading conditions and the quantitative relationships between freeze–thaw cycles and key parameters such as rock wall strength, surface roughness and basic friction angle. Finally, the influence mechanism of freeze–thaw cycles on the compressive strength, tensile strength and shear strength of intact rock and structural planes is explored from the perspectives of bonding and frictional effects. These research findings provide an important theoretical foundation for deformation control and stability analysis of engineering rock mass in cold regions.</p>