The Lurgi gasification technology has attracted significant commercial interest in China owing to its suitability for production of synthetic natural gas (SNG). However, hazardous trace elements (HTEs) in Lurgi gasification ash have the potential risk of contaminating surface and groundwater. In this paper, the HTEs in ash with different particle sizes from Lurgi gasifier and the HTEs concentrations of leachates were investigated by using an ICP-MS (Thermo Fisher, ELEMENT2/XR) and a direct mercury analyzer (DMA 80). Moreover, the mass loading (f(x)) and ecological risk index (RI) was introduced to evaluate the risk level of HTEs in Lurgi gasification ash with different particle sizes. The content of Be, Cr, Ni, Cu, Zn, Cd, Ba, Pb, U and As in fine ash (