To study the mechanical and hydrological mechanism of vegetation, the water absorption distribution function of plant root was introduced to describe the water uptake characteristics of different root architectures, and the calculation model considering the hydro-mechanical reinforcement of vegetation was established for the slope stability analysis. The rationality and validity of the model were verified by combining the experimental results. Considering the hydro-mechanical effects of different root architectures, the reinforcement effects of typical sections of bank slope in Hongze Lake embankment was carried out. The results showed that the matric suction of soil was significantly improved by the root water uptake, and the influence range was about 2.5 times the root depth; in the initial stage of root water uptake, the difference between different root architectures was small, but with the gradual increase of time, the difference between different root architectures gradually increased; the hydro-mechanical effects of vegetation can significantly improve the stability of embankment slope, and after 24 hours of rainfall, the factor of safety under root reinforcement is about 1.4 times that of bare soil bank slope.