Salt-induced deterioration is a major issue for earthen structures on the Chinese Loess Plateau. This study investigated the soil-water retention curve (SWRC) of loess with 2% Na2SO4 (C0S2) or NaCl (C2S0) using the contact filter paper method and a chilled-mirror dew-point hygrometer (WP4C). Mercury intrusion porosimetry (MIP) was used to examine pore size distribution (PSD) evolution during drying, while the small-strain shear modulus (Gmax) was measured via bender element tests. The results showed that salt-free loess and Na2SO4-amended loess followed a "bimodal-trimodal-bimodal" PSD evolution during drying, whereas NaCl-amended loess maintained a consistent bimodal pattern. Before crystallisation, Na2SO4 reduced micro- and meso-pores while expanding macro-pores, altering the pore structure. In contrast, NaCl maintained a more uniform pore size distribution, preserving the soil microstructure. NaCl also generated higher osmotic suction than Na2SO4, and the difference between both increased as Na2SO4 crystallised earlier. However, the influence of osmotic suction weakened as drying progressed. Before crystallisation, matric suction enhanced interparticle attraction, increasing Gmax, while osmotic suction provided additional tensile forces. As salts crystallised, osmotic suction declined, and pore filling stabilised meso-pore structures. In the final drying stage, osmotic suction became negligible, matric suction dominated, and Na2SO4 crystallisation expansion in C0S2 disrupted particle arrangements, potentially reducing Gmax.