Preferential flow is a major infiltration process in unsaturated soils. We conducted a dye-staining experiment in Beijing Jiufeng National Forest Park, in order to analyze the differences of soil porosity and soil moisture in preferential flow area and matrix flow area, as well as the effect of antecedent soil moisture (ASM) on preferential flow characteristics (i. e. , maximum dyed soil depth, 50% dyed soil depth, dyed soil percentage). Results indicated that: 1) the non-capillary porosity and the total porosity of the soil in preferential flow area were statistically higher than those in the matrix area, and no statistical difference in capillary porosity was found between the two areas; 2) soil moisture in the preferential flow area decreased by 21% after the experiment, while there was no difference in soil moisture in the matrix flow area;3) ASM was positively correlated with the dyed soil percentage (R² =0.679) and 50% dyed soil depth (R² = 0.527); in contrast, no apparent correlations were found between ASM and the maximum dyed soil depth (R² =0.236).