Soluble salts are an important cause of the weathering of stone relics. Accumulation and migration of soluble salts is inseparable from water. Salts in the top soil layer of Yungang Grottoes are an important source of the interior salts of Yungang stone relics. Therefore, it is of great significance to study the distribution characteristics of water and salts in the top soil layer of grottoes for the goal of reducing the accumulation of soluble salts in stone relics in the future. In our work, the saturated permeability coefficient, water content, void ratio and soluble salt content of soils at different depths and different locations in the top of Yungang Grottoes were systematically analyzed and tested. The distribution characteristics of water and salts in the top soil layer of Yungang Grottoes were studied in combination with the slope and vegetation coverage ratio at the sampling locations. The results show that 1) the higher the vegetation coverage ratio, the higher the water content of soil samples; 2) the larger the slope, the lower the water content of soil samples and 3) the void ratio and the saturated permeability coefficient show a linear relationship. The vegetation coverage ratio, slope and permeability are the main factors affecting the distribution of water and salts in the top soil layer of grottoes.