<p>Soil salinization is a major cause of structural degradation, strength deterioration, and deformation intensification in earthen heritage sites across northwestern China. Therefore, investigating salt-induced damage mechanisms in such soils holds significant engineering and conservation value . In this study, uniaxial compression tests were performed on soil samples with varying sodium sulfate (Na₂SO₄) contents (0%, 2%, 4%, and 6%) and different moisture levels (10%, 13%, 16%, 19%, and 22%). Resistivity measurements were simultaneously monitored to assess the electromechanical response of site soils during compression under different water and salt conditions. The results show that: (1) water content is the dominant controlling factor: both the uniaxial compressive strength (UCS) and electrical resistivity decrease monotonically with increasing water content. However, the rate of strength reduction diminishes markedly once the water content exceeds 16%. (2) Conversely, the influence of Na₂SO₄ was non-monotonic. The UCS initially decreased as salt content increased from 0 to 2%, likely due to the weakening of interparticle bonds, but then recovered at higher concentrations (up to 6%), suggesting the onset of salt crystallization-induced cementation. (3) This dual role of salt was mirrored in the electrical response: resistivity plummeted with initial salt addition, indicating enhanced ionic conduction, and then decreased gradually beyond 2% Na₂SO₄, consistent with a transition to a crystallization-dominated regime. These findings elucidate the complex interplay governing salt damage and highlight the potential of resistivity as a nondestructive indicator for assessing the condition of saline earthen heritage.</p>