Apparatus and method for cleaning chlorobenzenes-contaminated soil and groundwater are provided related to environment protection. The apparatus includes a direct current power supply, permeable reactive barrier (PRB) reaction walls and electrodes, wherein the electrodes are arranged in a polluted area according the concentric circles, and are installed into electrode chambers; the PRB reaction walls are installed at ½ between the anode electrode and the cathode electrode and at ¼ from the anode electrode. Chlorobenzenes in the soil and groundwater can be gathered in the PRB reaction walls through the arrangement of the electrode area; and then the chlorobenzenes can be further removed by oxidation-reduction reactions in the PRB reaction walls.