Ancient pyrometallurgical zinc generated large amounts of slag. Natural leaching from ancient pyrometallurgical zinc sites has contaminated the soil closed to the deposits. Electrokinetic removal was used to treat this slag. In this study, in order to evaluate the migration of heavy metals in electrokinetic removal, Visual minteq was adopted to calculate the species distribution of heavy metals in different pH. When pH is between 9.0 and 11.0,. Zn(OH)(2) is the main species. Cd(OH)(2) is the main species when pH is between 9.0 and 13.0. Hydroxide precipitation of zinc and cadmium was the main reason to restrict their migration. Arsenate always exist as an oxyanion such as AsO43, H2AsO4-, HAsO42-. Copper exists as anion form above pH 8.The enrichment of arsenic and copper near the anode occurred. This is probably due to the electromigration of negatively charged arsenic and copper ions towards the anode which would be faster than electroosmotic flow in the opposite direction. In a word, because of the heavy metal's enrichment in sample sections, the final removal efficiency rate of heavy was low. Some enhanced technology must be adopted to improve the removal efficiency rate.