Under the background of global warming and “carbon peaking and carbon neutrality” strategy, vegetation slope protection has become a potential means to reinforce the slope of negative carbon emission and errosion control. The development of vegetation roots can change the soil structure and hydraulic characteristics, and then affect the stability of slope. Although some experimental studies have explored the effects of vegetation on soil hydraulic characteristics under specific conditions, the general law that vegetation roots change soil hydraulic characteristics under different conditions is not clear.In this paper, the research on vegetation transpiration, root physical function and root biochemical function are collected and reviewed, the mechanism of the effect of vegetation roots on soil hydraulic characteristics is analyzed and summarized, and the available experimental data are statistically analyzed. It is pointed out that the change of hydraulic characteristics of soil by vegetation roots depends on the relative contributions of transpiration, physical and biochemical processes of roots, at the same time by the root type, soil type and growth stage and other factors. Therefore, the effect of vegetation roots on soil hydraulic characteristics is very complex, and more comprehensive and extensive researches are needed to reveal the mechanism of vegetation slope protection. Finally, the blank and future research trend of the effect of vegetation roots on soil hydraulic characteristics are discussed.