Root content has a 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-made infiltration experimental box was used to conduct quantitative research on the influence of different root diameters (1-3mm, 3-5mm, 5-8mm), 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 experimental 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. Statistical analysis of the experimental results reveals that the root surface area content is the primary factor influencing the saturated permeability of the rooted soil. A linear quantitative relationship is established between the root surface area content and the saturated permeability for different distribution types (horizontal and vertical) of roots. The rate of change in the saturated permeability of the root-soil composite with the root surface area content is approximately 1.8 times higher for vertically distributed roots compared to horizontally distributed roots. These research findings can be used to calculate the saturated permeability of the rooted soil and provide support for the stability analysis of vegetated slopes under rainfall conditions.