Improper disposal of chromium (Cr) and its compounds, especially hexavalent chromium (Cr(VI)), results in soil and ground water pollution and is consequently harmful to human health. In this study, three-dimensional electro-kinetic remediation of Cr-contaminated soil is investigated by coupling a two-dimensional electrode with a permeable reactive barrier (PRB) with a graphite electrode as the third electrode. Mixed zero-valent iron and zeolite are used as filling materials in the PRB. Moreover, three experimental conditions, i.e. two-dimensional electro-kinetic remediation with and without PRB and three-dimensional electro-kinetic remediation with PRB, are investigated herein. The results are evaluated based on the removal rate and leaching efficiency both in the pre- and post-experiments. Upon comparing the three conditions, the results show that three-dimensional electro-kinetic remediation with PRB has a better effect on both leaching efficiency and removal rate of contaminated soil. Single and multifactor experiments were designed to explore the optimum conditions on the basis of three-dimensional remediation. Graphite particles with a 5% dosage, resulted from the single-factor experiments, are used in the multi-factor experiments. The results show that the best remediation efficiencies are achieved after 12 d using 0.05 mol L⁻¹ citric acid and a voltage gradient of 1.5 V cm⁻¹ in three-dimensional electro-kinetic remediation coupled with PRB.