[Background] Forest vegetation plays a key role in soil erosion in Danjiangkou Reservoir area, and different vegetation has different ability on soil infiltration. Soil hydraulic properties drive water distribution and availability in soil. There exists limited knowledge of how plant growth especially surface root might influence soil hydraulic properties. Roots growing near the soil surface may influence soil detachment, and modify the properties of soil in their immediate vicinity. [Methods] To investigate the effects of root on soil infiltration capacity, the soil and root (two layers of 0 -10 cm and 10 -20 cm) of 35 samples representing the main vegetation types in Danjiangkou Reservoir area were surveyed and analyzed. The root structure characteristics and its influence on soil infiltration were studied, and the methods of modeling, correlation analysis and regression were introduced. [Results] The soil infiltration capacity of 0 - 10 cm soil layer of different vegetation types were higher than that of 10 - 20 cm. Soil initial infiltration rate and soil steady infiltration rate of 0 -10 cm and 10 -20 cm soil layer showed the same trend of the broadleaf forest > coniferous and broadleaf mixed forest > shrub > coniferous forest. Soil infiltration rate and soil steady infiltration rate had significant linear correlation with root length density and root surface area density among different vegetation types. The index of soil infiltration had significant correlation with root structure parameters of different root diameter ranged from 0.5 to 5 mm (P < 0.05). Kostiakov infiltration model, Philip infiltration model and Horton infiltration model stimulated the soil infiltration processing, and in Kostiakov infiltration model, root length density and root surface area density of different root diameter ranged from 0.5 to 5 mm presented the positive correlation with b values and negative correlation with a value. Root length density, root volume density and root biomass had significant correlation relation with the indexes of soil infiltration, which could be used to study the relation of root distribution and soil infiltration. The results indicated that vegetation types significantly affected soil infiltration, and coniferous and broadleaf mixed forest as well as broadleaf forest were better in soil infiltration and root structure. Root at diameter of 0.5 -5 mm played the key role in the root system on soil infiltration capacity. [Conclusions] The study promotes better understanding of surface root in different vegetation types and its influence on the soil infiltration, and suggests that coniferous and broadleaf mixed forest, and broadleaf forest should be protected, and shrub and coniferous forest should be transformed to promote the soil and water onservation capacity in Danjiangkou Reservoir area.