Soil water content (SWC) is of great importance to establish an appropriate irrigation scheme. The study object is 5-year-old dwarf apple trees under water storage pit irrigation method (depth 40 cm). In order to find an optimal SWC monitoring location, the distribution of apple tree fine roots (d≤2 mm) at different locations and SWCs within the root zone were studied and analyzed with regression and cluster analysis methods. The results showed that over 90% fine roots of apple tree were within 0~90 cm from the apple tree trunk in horizontal direction, while over 80% fine roots were within 0~120 cm from the apple tree trunk in vertical direction. The growth peak of fine roots was within 40~60 cm depth which accounted for over 40% of total fine roots. Meanwhile, the monitoring points were located at 90 cm away from the trunk (Dr90). SWC distribution in vertical direction of the Dr90 monitoring points was accorded with exponential function, with correlation coefficient greater than 0.8. Through sorting the SWC at six different depths in Dr90 with R type hierarchical clustering method, it showed that the soil moisture sensors in 60 cm can be used to represent the SWC condition within 0~120 cm depth. The SWC error between the simulations and observations in 2013 was within ±5%. The experimental results suggested that the profile (depth 60 cm) of SWC measured in the Dr90 was sufficient to estimate the water consumption amount under the water storage pit irrigation in the orchard.