The invention discloses an electric remediation device for heavy-metal contaminated soil and a method. The electric remediation device comprises an electrode assembly and a water circulation assembly,wherein the electrode assembly comprises a plurality of anode bars, a cathode metal mesh, a permeable wall and a filter screen, wherein the anode bars are vertically inserted into a soil region, thecathode metal mesh, the permeable wall and the filter screen are horizontally arranged in a surface cathode zone of the soil region, and the anode bars and the cathode metal mesh are externally connected with both positive and negative poles of a power supply separately; and the water circulation assembly comprises two inlet water tanks, an outlet water tank and a water barrier plate which are arranged around the soil region, the two inlet water tanks are located at two opposite sides, the outlet water tank is located between the two inlet water tanks, the water barrier plate is located opposite to the outlet water tank, the inlet water tanks and the soil region communicate with each other at bottoms, and the soil region is in overflowing communication with the outlet water tank. Accordingto the device and the method, by using electric energy and water potential energy, heavy metals in soil move to the top of the soil from the bottom of the soil and are combined with hydroxide radicals generated from electrolysis nearby a cathode to form hydroxide precipitates. Heavy-metal hydroxides are filtered and then are removed from a soil environment along with stripping of the permeable wall.