The treatment of mercury in flue gas of coal-fired power plants mainly relies on the collaborative removal of conventional pollutant purification devices. In order to understand the collaborative mercury removal capacity of pollutant purification facilities in ultra-low emission power plants in China,the field test data of mercury emission from power plants were statistically analyzed. The results reveal that the same type of pollutant purification facilities also have very different mercury removal capabilities. The mercury oxidation efficiency of selective catalytic reduction(SCR）is between 13.2% and 91.1%,and the average mercury oxidation efficiency is 52.7%. Different kinds of dust collectors show different mercury removal efficiency. Among them,LLT-ESP has the best mercury removal efficiency,followed by ESP+FF and ESP. The average mercury removal efficiency of wet limestone gypsum desulfurization system(WFGD）is 54.3%,which is mainly derived from the removal of Hg²⁺. The technical route with LLT-ESP as the core has the highest average mercury removal efficiency in different routes,which is 91.3%. The average mercury removal efficiency of the unit after ultra-low emission transformation is 80.1%,which is about 10% higher than that before transformation.