The leaching test with municipal solid waste incinerator (MSWI) bottom ash was studied in order to investigate leaching property of Cu and Pb and stabilization. Also carbonation reaction was processed in MSWI bottom ash and conform their effect on the leaching of Cu and Pb for maximization of weathering process. It was sampled one size of bottom ash lower than 0.15mm. In the leaching test of bottom ash (2 types) was resulted that leaching volume of Cu and Pb was high, although. Also dissolved Cu and Pb was investigated as a change of pH. Through interaction of $CO_2$ with bottom ash (carbonation), maximize stabilization of Cu and Pb leaching. As a result, leaching volume of Cu and Pb was decrease.