Abstract: An emissions studies for arsenic and mercury were conducted at a 300 MW coal-fired power plant. The solid streams such as coal, bottom ash and ESP ash were collected, and the arsenic and mercury in the flue gas around ESP were aslo directly sampled using Ontario Hydro Method and then tested. The results show that the arsenic concentration in fly ash is about 6.68×10^-6, which is almost 2.5 times as that in coal, nevertheless that in bottom ash is only 1.70 ×10^-6. Its concentration in the flue gas is 153.27 and 41.13 μg/m³ before and after ESP, respectively. The mercury concentration in coal, fly ash and bottom ash is about 2.5×10^-7, 1.9×10^-7 and 1.5×10^-7 respectively, its concentration in the flue gas before and after ESP was about 5.49 and 5.21 μg/m³. Arsenic is significantly concentrated in fly ash, whereas mercury is not. ESP unit has obvious synergistic effect on arsenic removal up to 71%, while it is not obvious for mercury removal.