The research on the stability of rock slopes under the multi-field coupling has important theoretical and practical significance for the analysis and prevention of freeze–thaw disasters of engineering in cold regions. In this paper, COMSOL Multiphysics numerical simulation software and numerical simulation methods are adopted. Based on the coupling theory of rock stress field, seepage field, temperature field, and chemical field, and field test data, the stability of rock slope under the multi-field coupling is studied under the research background of the highway slope of Jinghe to Yining County of G577 line. Based on the study of multi-field coupling theory, a numerical calculation model is established, the rationality of the numerical calculation model is verified, and the maximum frozen thickness of the slope is determined. On this basis, the change rules of the relevant parameters such as stress, temperature, deformation and damage of the highway slope in the engineering area are studied. The slope stability analysis is performed based on the YAI slope stability evaluation method. The stability of the slope is analyzed from the freezing, thawing and freeze–thaw process states of the shallow layer of the slope. It provides a theoretical basis for engineering construction in cold region.