Abstract: During the combustion process of coal, a large number of trace elements are discharged with flue gas and dust. Coal-fired power plants are the main force of coal consumption. With the continuous improvement of China's environmental protection requirements, the emissions of trace elements from coal-fired power plants have received extensive attention. The limestone-gypsum wet flue gas desulfurization (WFGD) system can not only efficiently absorb SO₂ in flue gas, but also affect the distribution of trace elements. In this study, environmental samples such as inlet/outlet smoke and dust, limestone, industrial water, sludge, gypsum and desulfurization wastewater were collected in the WFGD system of ultra-low emission units of three typical power plants in Anhui Province, and the distribution and migration characteristics of trace elements, including Cr, As, Cd, Pb and Hg, were analyzed. The results showed that the removal rate of trace elements in the smoke and dust was above 95%, the mass fractions of Cr, As and Hg in the desulfurized sludge reached 27~52 mg·kg^-1, 13~36 mg·kg^-1 and 4~6 mg·kg^-1, respectively, and the mass concentrations were about 7~9 times those in the gypsum. The element mass balance results showed that the main sources of trace elements in the WFGD system were flue gas (90%) and limestone (10%), and the main outputs were sludge (42%) and gypsum (61%). Only a small amount of Cd (7%~10%) and Hg (13%) was enriched in the wastewater. This study indicated that the disposal and secondary utilization of desulfurized gypsum and sludge should focus on the environmental effects of trace elements.