Abstract: The chlorine saline soil is a typical type of saline soil in the cold and arid regions of Northwest China, and its electrochemical characteristics are crucial to understanding of the corrosion mechanism of saline soil. To explore the relationship between the phase transition of pore solution in saline soil and its electrochemical characteristics, the sodium chloride saline silty clay is taken as the research object, and its electrochemical impedance spectra are measured under different salt content and temperature conditions. The results reveal that the impedance of the sodium chloride saline soil gradually decreases with the increase of frequency, and reaches stable state at high frequency. The logarithm of the impedance modulus of the sodium chloride saline soil increases linearly with the decreasing temperature before freezing, while the generation of ice crystals and salt crystals leads to a significant increase in the impedance modulus of the soil after freezing. The sodium chloride saline soil exhibits a capacitive impedance arc before freezing, while the migration of soil water and salt caused by phase transition results in a diffusion impedance of the soil after freezing. Based on the conductivity path of the soil before and after freezing, the equivalent circuit model for the soil before and after freezing is established, and the relationship between the phase transition of the soil pore solution and the corresponding circuit components is analyzed. It is of great significance for understanding the electrochemical characteristics of saline soil and the phase transition process of pore solution.