Soil secondary salinity and fresh water shortage are two major problems limiting crop growth and yield improvement. Therefore, analysis of effects of sand mulching on soil water infiltration, evaporation, and salt transportation is of some great significance to optimizing the method of sand mulching in arid regions. A laboratory simulation experiment was conducted to study processes of soil water infiltration, soil water evaporation, and salt transportation under sand mulchings different in thickness, in the condition of constant water head infiltration and simulating steady evaporation. The sand used in this study varied from 0.2 mm to 2 mm in particle size. The experiment was designed to have four treatments in sand mulching, i e., 0 (control), 1.7, 3.6 and 5.7 cm, in thickness of the sand layer on the surface of soil. Results show that (1) Sand mulching has an obvious inhibitory effect on soil water net infiltration, and the thicker the sand mulching the less the soil water infiltration, namely, the effect increases significantly with the thickness of the sand mulching; (2) Sand mulching dramatically reduces soil water evaporation, and the thicker the sand mulching the less the soil water evaporation, demonstrating a significant positive correlation between soil water evaporation from surface and the thickness of the sand mulching; and it was found that during the 20 days of experiment, the evaporation process in the sand mulching treatment was rather stable, and the soil water cumulative evaporation fitted a linear equation and the Rose empirical equation as well; (3) Sand mulching alters soil salt transportation and distribution in soil profile, especially reducing accumulation on the top-surface soil layer. To sum up, sand mulching significantly inhibits soil water evaporation from soil, and surface accumulation of soil salt. Sand mulching, 1.7 cm or more in thickness, is sufficient to create the effect, but it also affects net infiltration of the soil. To sum up, sand mulching significantly inhibits soil water evaporation from soil, and surface accumulation of soil salt. Sand mulching, 1.7 cm or more in thickness, is sufficient to create the effect, but it also affects net infiltration of the soil.