Root content has significant influence on the saturation permeability coefficient of soil, but there is a lack of quantitative research on the effect of coarse tree roots on soil saturation permeability coefficient. In this study, a self-developed infiltration experimental box with constant head method was used to conduct quantitative research on the influence of different root diameters （1 mm≤d≤3 mm、3 mm<d≤5 mm, and 5 mm<d≤8 mm） root content (root volume content: 0.4%-2.4%), and root distribution forms (horizontal and vertical) on the saturation permeability coefficient of remold root-soil. The results indicate that, under the same root diameter conditions, the saturated permeability of the rooted soil is linearly and positively correlated with the root volume content. However, as the root diameter increases, the slope of this linear relationship continuously decreases. There is also a significant correlation between the saturated permeability coefficient and the root surface area content, and the variance analysis shows that the relationship is not affected by root diameter. Meanwhile, the linear relationship between the root surface area content and its saturation permeability coefficient was determined under different distribution types of roots (horizontal and vertical). In addition, it was found that the change rate of the saturation permeability coefficient of the rooted soil with the root surface area content in the vertical distribution was about 1.8 times that of the horizontal distribution. Based on the results above, it can be seen that the presence of roots can significantly improve the saturation permeability coefficient of soil, and the surface contact of root soil is the fundamental reason affecting its hydraulic characteristics.