The purification degree of heavy metal contaminated soil directly affects its reuse. This paper took the soil contaminated with Cd, Cu, Ni, Zn and Pb as the research object, and the improved surround electrode arrangement as the testing method. The purification degree and soil properties of contaminated soil under phytore-electric coupling remediation were used as indicators to examine the key factors and reveal the enhancing mechanism. The results demonstrate that the removal rate of phytore-electric coupling remediation is higher than that of single one, and the occurrence form of heavy metals and the response of plants to heavy metals are the key factors. The method of improved surround electrode arrangement can actively mobilize the migration and then accumulation of heavy metals in a larger range of soil to plant roots, and then solve the problem of low accessibility and biological activity of heavy metals in sole phytoremediation. The assistance of phytoremediation is beneficial to relieve the adverse effects of electrokinetic remediation on soil properties, and solves the problem of concentrating effect and high energy consumption. The coupling remediation combined the improvement of spatial distribution and bioavailability of heavy metals, metabolism of plant, and life activities of soil microbial, which effectively improve the purification of heavy metal contaminated soil. After remediation, the soil can maintain a stable pH of 6.27-7.91, and a conductivity of 108-159 μs/cm. In addition, the energy consumption is only 13.76-18.81 kW·h/m³. The phytore-electric coupling remediation method helps to promote the sustainable use of contaminated soil.