Aiming at complexity of the root architecture, low efficiency of typical numerical simulation method and difficulty of modelling large deformation, a root system reconstruction method was proposed on basis of Winkler foundation beam theory. The individual roots were simplified into horizontal or vertical cylindrical elements while preserving key root distribution characteristics. Two types of complex root system models were built: a narrow-deep model A and a wide-shallow model B, together with their simplified versions Am and Bm. The bending moment-rotation curves and the failure mechanisms before and after root system reconstruction under centrifugal conditions were compared. The initial stage of moment-rotation curves showed high consistency between original and reconstructed models. Model B and Bm exhibited similar responses under large displacement, whereas the tap root in Model Am was broken due to stress concentration, leading to 65% moment reduction. Windward lateral roots were pulled out of the soil, consistent with the field observations. The simplified model accurately reproduces the overturning resistance and effectively captures the failure mechanisms dominated by taproot fracture, providing theoretical basis for physical and numerical modelling of complex root systems.