In order to understand how apple trees influence the orchard soil moisture, the characteristics of orchard soil moisture under different planting-year were investigated. The results showed that the orchard soil moisture in gully region of Loess Plateau was deficient for it was generally lower than the 80% of field capacity. The average soil water content at 0-10 m depth had extremely significant correlation with those of the layers below 3 m, had significant correlation with that of the 2-3 m layer, but had no correlation with that of 0-2 m depth. With the increase of planting-year, soil water content decreased firstly and then increased, soil water volatility and the quantity of water deficit increased firstly and then decreased, the water depth available to the roots deepened. The deepest water depth available to the roots could reach to 8m during the lifecycle of apple trees.