This work was done to develop a methodology for analysis of heavy metals in municipal solid waste incineration (MSWI) slag. It performed analysis of heavy metal content, leaching concentration as a function of pH and vibration time. It was found that content of heavy metals followed the decreasing sequence of Zn > Pb > Cu > Cd. Proper vibration time period was 1.0 h for extraction of theses metals, and their leaching concentrations increased with increasing pH from 1 to 11. Hence, an acidic environment could enhance leaching of the four heavy metals.