Under the action of freeze-thaw cycle, the cement-soil subgrade in the season frozen area often occurs the phenomenon of overturning and frost heaving, which threatens the road safety. According to the law of attenuation of elastic modulus, freeze-thaw damage variables are defined, assuming that the strength of the loaded damage microelement follows the Weibull probability density distribution, and the load damage variables are obtained. Based on the relationship between the loaded microelement and the freeze-thaw microelement of cement soil, the total damage variables of freeze-thaw and load are constructed. The damage correction factor is introduced to establish a new statistical damage model of cement soil under freeze-thaw cycle. Based on the experimental results and linear regression curve fitting method, the model parameters are obtained. The triaxial compression test of cement soil under different freeze-thaw cycles is carried out to analyze the law of damage accumulation, and the test data of cement soil are identified by using the model to prove the rationality and feasibility of the model. The research results provide some reference for the simulation of mechanical behavior of cement soil under freeze-thaw cycle and the design, construction and maintenance of highway subgrade in seasonal freezing area.