Abstract: Abstract: Preferential flow is a main type of soil water movement in the structured soil. Although previous researches have made a great progress in preferential flow, how to compare the level of preferential flow based on the dyed pattern of soil profile by dyeing tracers is not reported yet. Therefore, in this paper, the Brilliant Blue FCF (C.I. 42090) dye tracer experiment was designed to investigate and quantify the preferential flow in five intact and five disturbed soil columns sampled at the depth of 0-100 cm from the Experimental Station of the Institute of Hydrogeology and Environmental Engineer, Chinese Academy of Geological Science (Hebei, China) and from Luancheng Experimental Station of Chinese Academy of Science (Hebei, China). Soil water movement patterns of the intact and disturbed soil columns were compared. The results showed that the preferential flow was developed in the intact soil columns, while the piston flow in the disturbed soil columns. The characters of preferential flow in the soil profiles varied along both horizontal and vertical directions. The coefficients of variation (C.V) of the dyed area percentages in the whole profiles of soil columns were proposed to quantify preferential flow in the undisturbed columns and the capacity of soil water movement in the disturbed columns as long as 1) the irrigation conditions were same for all columns; 2) the area of preferential flow was larger than that of uniform flow in intact columns; and 3) the mass-transfer coefficients of soil water flowing horizontally from the preferential path to the matrix were same. Small C.V value represented the high levels of preferential flow in the intact columns. The C.V≥0.5% indicated the low levels of preferential flow, while C.V of >0.25%～<0.5% and ≤0.25% suggested the medium and high levels, respectively. However, the estimated principle may be not suitable for intact soil columns with different kinds of preferential path, i.e., soil cracks and plants' root and earthworm burrows. The preferential levels of the soil columns assessed by the C.V of the dyed area percentages were verified successfully by the irrigation test of undistributed and distributed columns designed to quantify the percentage of preferential flow. However, the results of preferential flow levels estimated by the C.V may be affected by size of columns, because the characters of preferential flow varied with study scales. Therefore, more studies were needed to verify the feasibility of C.V in estimating the preferential flow level. The study here proposed a quantitative method to assess the preferential flow level directly from the dyed pattern of the soil profile, and to evaluate the groundwater recharge, saving water and soil polluting in agriculture.