Abstract: 【Objective】The present study aimed to reveal the reaction characteristics of Cr( Ⅵ ) adsorbed by paddy soil and examine the reduction effect of Cr( Ⅵ ) by zero-valent iron ( ZVI,) in the soil, and analyze the effect of relative factors on the above-mentioned process. 【Method】The batch isotherm adsorption and kinetics experiments were performed to investigate the effects of reactant concentration, reacting time, pH, ionic strength and accompanying anions on the adsorption and reduction of Cr( Ⅵ ) in the mixed system of paddy soil and ZVI. The experimental data was also analyzed with adsorption and kinetic model.【Result】The adsorption saturation was not obtained with the initial concentrations ranging from 0.1 to 2.0 mmol/L and the adsorption isotherm could be well fitted by Langmuir equation (R2=0.9963). The increase in pH and ionic strength was unfavourable for Cr( Ⅵ ) adsorption and the kinetic curve could be properly fitted by pseudo-first-order kinetic equation (R2=0.9935). With the introduction of ZVI, the added Cr( Ⅵ ) (0.20 mmol/L ) was totally transformed to Cr( Ⅲ ) under the present reaction condition, and the calculation of aqueous Cr mass balance indicated that a certain amount of the generated Cr( Ⅲ ) were adsorbed by the solid surface. The presence of phosphate and 1,10-phenanthroline could inhibit the Cr( Ⅵ ) reduction. Moreover, Cr(VI) reduction would be suppressed as the solution pH increased, evidenced by the reduction percentage decreased from 100% at pH 4.34 to 56.3% at pH 6.87. 【Conclusion】The electrostatic adsorption was involved in Cr( Ⅵ ) adsorption by the paddy soil. The enhancement of electrostatic repulsion between the soil surface and Cr( Ⅵ ) and the competitive adsorption between Cr( Ⅵ ) and chloride ions contained in the supporting electrolyte could jointly decrease the Cr( Ⅵ ) adsorption in the soil. Low pH was favourable for the occurrence of Cr( Ⅵ ) reduction by ZVI in the soil, and the reduction would be inhibited in the presence of phosphate and 1,10-phenanthroline.