The treatment of soil contaminated with trichloroethylene (TCE) is demonstrated. In the present study, electric osmosis was applied to the removal/decomposition of TCE. First. the behavior of water and TCE in electrolyte (KNO3) solution was examined with electricity supply. The permeation rate of electrolyte (KNO3) solution through a cylindrical unglazed plate was increased with increased voltage and concentration of electrolyte. On the other hand, the diffusion rate of TCE without electricity was increased with addition of electrolyte, while the rate was negligibly small. The TCE added to the inside solution (anode side) mostly stayed inside and was completely decomposed. Based on the above results, the decomposition of TCE in soil was tried. The contaminated soil at the outside of the cylinder was moved and decomposed in the initial stage, however, the rates were reduced and its concentrations in both solutions were increased with the decrease in current density. Therefore, the electrolyte was added periodically, which increased current density. leading to the decomposition of TCE in both sides. Finally more than 99.9% decomposition of TCE added to the soil was demonstrated by 10 h electric osmosis with a 10 voltage.