Abstract: The mechanical properties of the interface between saline frozen soil and concrete have an important impact on the stability and durability of road engineering structures in cold and dry areas. In order to reveal the mechanical characteristics of the contact surface between saline frozen soil and concrete under the action of multiple factors, the shear stress-displacement relationship and shear strength of the contact surface were studied through laboratory tests and mathematical models. Firstly, the direct shear test of saline frozen soil-concrete interface was carried out under the conditions of water supplement and no water supplement, freeze-thaw cycle mode (one-way freeze-thaw cycle and overall freeze-thaw cycle), freeze-thaw cycle number (0, 5, 10, 20), salt content (0, 0.5%, 1%, 2%, 3%, 4%), salt content type (NaCl and Na₂SO₄), shear temperature (-2 ℃, -5 ℃, -10 ℃), etc. Secondly, the relationship between shear stress and shear displacement of the contact surface is fitted based on the Gomez model, and the applicability of the model is evaluated. Finally, the grey correlation theory is used to analyze the correlation between each influencing factor and the shear strength of the contact surface, and the significance ranking of each influencing factor is established. The results show that the influence of freeze-thaw cycles on the shear strength of the contact surface is not obvious, but as the number of freeze-thaw cycles increases, the shear strength of the contact surface gradually decreases. The shear strength of the contact surface decreases with the increase of salt content. When the salt content exceeds 2%, the shear strength of the contact surface of sodium sulfate and sodium chloride frozen soil presents an opposite change rule, and the strength of the contact surface of sodium sulfate frozen soil increases. When the temperature drops to -5 ℃ or lower, the water supplement condition enhances the shear strength of the contact surface. The Gompaz model is in good agreement with the stress-displacement relationship of the interface between saline frozen soil and concrete, and can be used to evaluate the shear characteristics of the soil-concrete interface in the cold and dry saline soil area. According to the grey correlation analysis, the order of significance of each influencing factor is: moisture content>shear temperature>freeze-thaw cycles>sodium chloride salt content>sodium sulfate salt content.