Abstract: In order to understand the mercury removal mechanism by adding oxidant ant its impact on other byproducts, the application and study of bromide-blended coal combustion technology are conducted in a 600MW coal-fired unit. The mercury concentration and speciation in flue gas is sampled by U.S. Environmental Protection Agency (EPA) 30B method before and after wet flue gas desulfurization (WFGD), and the mercury concentration in by-products are analyzed. The results show that after addition of calcium bromide, the mercury oxidation rate of flue gas and mercury enrichment factors of fly ash increase greatly. When bromine/coal ratio is 28.3 mg/kg, overall mercury removal rate reaches 96.8%. The halogen concentration and speciation of flue gas before and after selective catalytic reduction (SCR), electrostatic precipitator (ESP) and WFGD is sampled by EPA 26A method. It is found that the addition of calcium bromide will not result in additional halogen emissions, all the bromine in flue gas exists in the form of HBr, and no bromine emissions are detected after WFGD. The leaching toxicity and thermal stability test results show that the addition of calcium bromide will not affect the leaching toxicity of by-products and the thermal stability of mercury in gypsum. Instead, it improves the thermal stability of mercury in fly ash. In addition, the test methods of mercury concentration in flue gas and bromine concentration in fly ash are analyzed, and the main reaction paths are deduced based on the test results. Taken together, the mercury oxidant addition technology can improve the overall mercury removal efficiency of the power plant, and no significant negative effects are found.