Abstract: The simulated earthen columns with different salt contents and compositions were prepared with the aid of materials and techniques used to produce the fresco floor layer of the Mogao Caves murals. The alumina spheres were placed at different locations of the column as the salt migration probes to investigate the distribution and migration of sodium sulfate and sodium chloride and their crystallization behavior on the surface of the column. In order to investigate the effect of differences in components and pore properties of the fresco floor layer of the Mogao Caves murals on salt migration and crystallization processes, probe pellets placed at different locations and soil at the same location were sampled. The effects of different pore structures and properties on water-salt transport and distribution, and the differences in the crystalline behavior of probe pellets and soil surfaces on the surface of the simulated earthen columns for different salts were investigated by Brunner-Emmet-Teller measurements (BET), scanning electron microscopy-energy spectroscopy (SEM-EDS), and other methods. The ion chromatographic (IC) method was used to analyze the salt ion concentration at different heights of the simulated earthen column to detect its migration properties and distribution characteristics, so as to obtain the effect of different components of the fresco floor layer of the Mogao Caves murals on water-salt transport and salt crystallization. The results showed that the pore properties and structure of the water-salt transport medium have a great effect on the generation and development of the salt damage. The high content of wheatgrass in the fresco layer is conducive to the migration of water and salt solution to the surface of the fresco layer, while the presence of fine linen enables the increases of the number of soil mesoporous in the soil, both of which promote the nucleation and crystallization of the salt closer to the surface of the fresco layer, posing a threat to the existence of surface murals. The crystallization behavior of salts and mechanism of salt damage are also different. Sodium sulfate is more likely to crystallize on the surface soil layer of the simulated earthen column, while sodium chloride mainly crystallizes on the surface layer of alumina pellets. When the two salts are exist simultaneously, the crystallization of sodium chloride mainly occurs on the surface of alumina pellets on the simulated earthen column, but the crystallization of salt on the surface layer of the soil is weakened.