MSWI fly ash is regulated as hazardous waste in many countries as it enriches heavy metals and many toxic components and these components would potentially leach when the ashes are land filled. In this study, the basic characteristic of fly ash was ananlysised. The result of XRF showed that the main elements in fly ash were Cl, Ca, K, Na, S, O, C, Si, Al, where Zn, Pb, Cr, Cu were the main heavy metals . The SEM analysis showed that the fly ash mainly formed with amorphous structure and was polymerized by many tiny structures. What's more, after electrokinetic removal experiment, extraction toxicity tests was carried out to investigate the environmental toxicity of the MSWI fly ash. It was determined that the original the extraction quantity of heavy metals was obviously higher than the “standard for pollution control on the landfill site of municipal solid waste” and the electrokinetic removal technology showed the effect on reducing the extraction quantity. However, some sample still could not reach the standard, further work should be done to improve it.