Three soils with different texture(sandy loam,eolian sand,warp clay) were selected in Huang-Huai-Hai Plain.Each treatment consisted of two 1.5m by 1.5m plots,one of which had been irrigated with about 56kg water two days before the dye experiment to achieve different initial water contents.Brilliant Blue was chosen as the dye tracer.One day after the irrigation,a vertical lm by lm soil profile was prepared.Photographs were taken for graphics analysis.And the relations between the occurrence of preferential flow and soil type,initial water content were studied.The results showed that susceptibility of different soils to preferential flow was different Structured soils were more prone to produce bypass flow.The initial water content had a pronounced effect in sandy loam soil and eolian sand soil and no effect in warp clay soil according to the deepest transport depth of the dye.The preferential transports of paclobutrazol and Cl^- were carried on sandy loam soil.Cl^- was detected at every site where preferential flow existed and had a much higher content than soil background content Paclobutrazol could also be detected even at the deepest transport depth of the dye.