Heavy metals such as cadmium, copper, arsenic, mercury, lead, hexavalent chromium, zinc, nickel have been treated by blocking the migration of the heavy metals, because they could not be decomposed naturally. Recent approach is studied to separate the heavy metals from the soil, but there is a problem to increase the processing cost compared to the other treatment processes. Physiclal pre-treatment could concentrate heavy metals and improve the efficiency of the overall process. Gravity concentration can be used to treat heavy metal contaminated soil due to the difference in specific gravity. Chemical treatment such as soil washing has been used to remove the heavy metals from soil contaminated by leaching. In the conventional processes, strong acids were used to remove heavy metals but they could acidify the soil after treatment, so further neutralization process will be required. In the present study, the chemical form of Pb, Cu, and Zn in the contaminated soil sampled in the shooting range was analyzed using the sequential extraction method bound to exchangeable, bound to carbonate, bound to Fe-Mn oxides, bound to organic matter, and residue. Citric acid leaching is useful to extract heavy metal contaminants in bound to exchangeable, bound to carbonate, and bound to Fe-Mn oxides. Therefore, gravity concentration treatment followed by citric acid leaching could remove successfully heavy metals contaminants from the contaminated soil.