The sintering process is used to stabilize the heavy metal in fly ash from municipal solid waste incinerator (MSWI). Migration characteristics of 6 targeted heavy metals (Cd, Pb, Cu, Ni, Cr and Zn) in the sintering process of MSWI fly ash were investigated by experiments. Effect of several factors including sintering temperature, residence time, molding pressure and particle diameter on the migration of heavy metals were discussed in details. The results show that cadmium and lead are volatile metals, while nickel, copper, chromium and zinc belong to involatilizable metals. The effects of sintering temperature, residence time, molding pressure and particle diameter on the stabilizing efficiency differ from each other. The study shows that most of heavy metals are stabilized during the sintering process. The stabilizing efficiency of heavy metals was different for different elements.