Abstract: The physiochemical properties and heavy metal pollution characteristics of fly ash from a waste incineration plant in Shanghai were studied and analyzed. The results showed that the fly ash surface area and pore volume decreased obviously, and the chloride content also decreased greatly after refuse classification. Except Zn and Cu, the contents of other heavy metals increased after refuse classification, and the leaching concentration of Pb was far higher than the concentration limit of Standard for Pollution Control on the Landfill Site of Municipal Solid Waste (GB 16889-2008), which was of high environmental risk. Therefore, the fly ash must be disposed of harmlessly. Due to the change of Pb, Cd, Zn contents and their unstable forms, the leaching concentrations under acidic condition increased significantly which posed a great potential threat to the environment.