The present invention relates to a system and a method to purify contaminated soil using a radial-shaped horizontal injection well, and a horizontal extraction well comprising: a main vertical well (10) vertically formed in a soil and perforates the soil; a plurality of horizontal injection wells (1) arranged in a radial shape with respect to the main vertical well (10) in the contaminated soil (S); and a horizontal extraction well (2) installed in a radial shape in the contaminated soil (S) and in the gap between the horizontal injection wells (1) with respect to the main vertical well (10), and is alternately located on the horizontal injection well (1); thus supplying a contamination removal agent in the horizontal injection well (1) and injecting the same in the contaminated soil are allowed to discharge the contaminated substances and the contamination removal agent received in the horizontal extraction well (2) out of the soil.
