The effect of three extractants, which are HNO3/NaOH, CH3COOH/NaOH, and HNO3-H2SO4 , on leaching characteristics of the fly ash from municipal solid waste incinerator (MSWI) was investigated. The results showed that: (1) different extractants had different buffering capacities for the leaching solutions of the fly ash from MSWI, which are in the order of HAC > HNO3-H2SO4 > HNO3. (2) HAC showed better dissolvability to Zn, Cd, and Cr than HNO3-H2SO4, under more acidic condition, but the leaching concentration of Pb was not affected by extractant types obviously. (3) The leaching concentrations of Pb and Zn reached their maximal values at the ratio of liquid to solid of 40, while Cd leaching concentration did at the ratio of 20, and the leaching concentrations of Zn, Pb, Cd, and Cr decreased gradually with the increase of the ratios of liquid/solid when HNO3 and HNO3-H2SO4 extractants were used.