Abstract: Artificial freezing is a commonly used method for stopping water and providing temporary support during the excavation of saturated sand. This study on the damage characteristics of frozen soil lays the foundation for the analysis of the mechanical properties of frozen soil and the stability of frozen bodies. In order to study the damage mechanical properties of frozen sand, three-dimensional laboratory tests on frozen sand with different intermediate principal stress coefficients were carried out at -5℃. Based on the Weibull random distribution of micro element failure of frozen soil, the Drucker-Prager strength criterion was invoked as the statistical distribution variable, and the strain equivalence hypothesis was used to establish the damage constitutive model of frozen sand under three-dimensional stress state. On this basis, the model parameters F₀ and m are discussed the damage constitutive model of frozen sand under the influence of medium principal stress coefficient is established by modifying the model parameters reasonably and comparing with the test results. The results show that the parameters F₀ and m decrease first and then increase along with the increase of the intermediate principal stress coefficient; the parameter F₀ reflects the strength characteristics of frozen sand, and the parameter m represents the ductility and brittleness of frozen sand. The damage constitutive model of frozen sand considering the influence of medium principal stress coefficient can effectively simulate the whole stress-strain curve of frozen sand. The research results provide a theoretical basis for the engineering design of an artificial freezing method.