Objectives：On account of limited understanding and inadequacy studies, the current standards of landfill environment and pollutants control both lack of the upper limitation for Polycyclic Aromatic Hydrocarbons(PAHs) in landfill leachate, which is a kind of carcinogenic, teratogenetic and mutagenic persistent organic pollutants. Based on the investigation of 831 landfills in 306 cities of China, PAHs were detected in almost all of the fresh leachate, and even groundwater beneath the landfills was polluted. So far, research about PAHs’ partition and migration behaviors in porous media have focused on PAHs in surface polluted water, farmland sewage irrigation, crop soil and riverbed sludge, while reports about PAHs in landfill leachate sorbed and migrating in clayed soils beneath landfill sites are scarcely found. Furthermore, in North China plain and other area, the clayed soil in the vadose zone is the main layer which can reduce the aquifer’s pollution level. For above reasons, research about the mechanisms and disciplines of PAHs’ partition behavior in clayed soil in leachate are meaningful.Methods：Taking one landfill in North China plain for example, this study have chosen Naphthalene and Benzoperylene as research objects, the transport abilities of which are strongest and weakest, respectively. Based on field investigation, samplings and chemical analysis, experiments of adsorption kinetics and isothermal adsorption were conducted, during which two kinds of background solutions were used——the 0.01mol ·L-1 CaCl2 solution and fresh landfill leachate, respectively. By this way, the mechanisms and disciplines of PAHs in landfill leachate adsorbing on clayed soils in the vadose zone were revealed.Conclusions:① Landfill leachate can enhance the capability for calyed soil to absorb Naphthalene, but it has nearly no influence to help the soil to absorb Benzoperylene. ② In the 0.01mol·L-1 CaCl2 solution, the Naphthalene and Benzoperylene adsorption regularities on calyed soil meets the linear equation; In landfill leachate, for the 2ring PAH Naphthalene and 6ring PAH Benzoperylene, Freundlich equation and Lamguir equation are more suitable, respectively. ③ The retardation factors for Naphthalene and Benzoperylene in leachate pertain to these PAHs concentrations, and the relation are complex. As for the same equilibrium concentration of PAHs in liquid, the clayed soil’s retardation factor to Benzoperylene is 1~8 times of it to Naphthalene. ④ In adsorption experiments both in 0.01mol·L-1 CaCl2 solution and in landfill leachate, the primary concentrations of Naphthalene and Benzoperylene in the liquid have a good linear correlation with the equilibrium adsorption quanttity of calyed soil, and the regulations are similar.