Abstract: 【Objective】 To comprehensively and accurately understand the spatial distribution of walnut tree roots in different planting years in southern Xinjiang, and scientifically carry out fertilization management. 【Methods】 The walnut trees with different planting years in Wensu County of Aksu Prefecture in southern Xinjiang were taken as research objects. The spatial variation of walnut roots in 5, 10, 15 and 20 years was investigated. 【Results】 The results showed that the dry weight density of roots increased with the increase of walnut age, and the horizontal and vertical depths increased. The total dry mass of roots also increased. The root system of 5-year-old walnut trees mainly concentrated 0-100 cm in the direction of trees II and III, and the depth was 0-40 cm; 10-year-old tree was 50~150 cm in the direction of I and III from the tree level, and the depth was 0-40 cm. At 80-100 cm; 15-year-tree was 150-250 cm in the direction of tree I and III, and the depth was 20~80 cm; 20-year-old tree was 0~150 cm in the direction of tree II and III, and the depth was 0-80 cm. 【Conclusion】 With the increase of years, the roots of walnuts continue to extend horizontally and vertically, and the parts of fertilization should be widened and deepened with the distribution of roots.