Abstract: A field measurement study was conducted on typical grate furnaces (GF) and circulating fluidized bed (CFB) waste incinerators. Flue gas and by-products (bottom ash and fly ash) were collected before and after different flue gas purification devices for analysis, aiming to elucidate the migration and transformation characteristics of mercury in the tail-end flue gas. The results indicate that mercury in the flue gas primarily exists in the form of Hg²⁺, followed by Hgᵖ, with Hg⁰ accounting for a relatively small proportion. The concentration of mercury in the flue gas exhibited significant temporal fluctuations, and notable variations were observed among different power plants. Different pollution control facilities demonstrated varying capabilities in mercury transformation and removal. The semi-dry acid removal tower promoted the conversion of Hg²⁺ to Hgᵖ, while the baghouse filter exhibited high removal efficiency for various mercury species (54.35%~95.60%). After incineration, mercury in the waste was less enriched in the bottom ash, with the majority migrating to the fly ash, accounting for 78.27%~93.39% of the total. Compared to grate furnaces, the release proportion of mercury during CFB incineration was higher. The mercury emitted into the atmosphere was predominantly in the form of Hg²⁺, with a total emission factor ranging from 0.008 to 0.526 mg/kg.