<p>Root-reinforced soils are increasingly used in ecological slope protection, yet their mechanical behavior remains insufficiently described in current numerical modelling approaches. In this study, a hypoplastic constitutive model for root-reinforced soil is proposed. The mechanical reinforcement effect of plant root is incorporated by modifying both the critical state stress ratio and the critical void ratio as functions of root content. The proposed model is implemented within a finite element framework using an explicit integration scheme combined with a stress-correction procedure to ensure numerical stability. A series of benchmark simulations, including triaxial and direct shear tests on root-reinforced soil, are performed to validate the model performance. The applicability of the model is further evaluated through numerical simulations of rainfall-induced instability in vegetated slopes. The results indicate that the proposed approach provides a practical framework and an effective computational tool for analyzing and designing vegetated slopes.</p>