<p>The interfacial mechanical properties of frozen soilbag-expansive soil play a key role in the long-term stability of the expansive soil slopes reinforced by soilbag in seasonally frozen regions. However, the freezing effect on shear behavior of soilbag-expansive soil interface is still unclear. In this study, a series of large-scale temperature-controlled direct shear tests was conducted on frozen soilbag-expansive soil samples with different temperatures (-15℃, -10℃, -5℃ and -2℃) and normal stresses (25kPa, 50kPa, 100kPa and 200kPa). Effects of temperature and normal stress on failure morphology, shear stress–shear displacement relationship, volume change behavior, and shear strength characteristics are analyzed. Two primary areas can be distinguished on the soilbag-expansive soil interface: the contact surface area (CSA) between the woven bag and expansive soils, and the embedded soils area (ESA). The shear failure displacement (<i>δ</i>_p), friction angle (<i>θ</i>), maximum dilation angle (<i>ψ</i>_max), interface cohesion and interface friction angle are used to quantify the shear behavior of frozen soilbag-expansive soil interface. Furthermore, the evolution mechanism of stress-dilatancy characteristics and the influence of the embedded soils are discussed. The experimental findings are expected to provide theoretical insights for the construction and operation of expansive soil slopes reinforced by soilbag in cold regions.</p>