Taking liana vegetation and secondary arbor forest in Yongding (Beijing section) riverside as the research object, this paper studied preferential flow characteristics of the section dyed pictures and infiltration water volume by using the methods of field dyeing tracer, root system analysis, morphological and statistical analysis. The results showed that the depth of matrix flow in the sample plot covered by liana vegetation was 5.48 cm smaller than that in the secondary arbor forest, and the number of channels with preferential flow paths was 67% more than that in the secondary arbor forest. The phenomenon of preferential flow was more obvious in liana vegetation sample plot, and the average dyeing area ratio (34.17%), preferential flow ratio (69.44%) and length index (457.79%) were 9.89%, 18.66% and 25.71% larger than those of arbor forest plot, respectively. In the two kinds of plots, the root length density decreased with the increasing of soil depth. The root length density of 0-10 cm surface soil layer in liana plot was 2.96 times higher than that in secondary arbor forest. The relationship curve between dye area ratio and root length density was well fitted, and the correlation index R² of liana plot was 0.97. Under the same external conditions, the soil under liana vegetation had higher preferential flow degree than that under secondary arbor forest.