Abstract: In order to study the effect of flue gas injection temperature and adsorbent injection amount on mercury removal efficiency in coal-fired flue gas,1% NH_4Br solution was used to impregnate and modify rice husk coke to prepare mercury removal adsorbent NH_4Br modified rice husk coke( Br-RHC).The pore structure of the adsorbent before and after modification was characterized by specific surface area and porosity analyzer,and the experiment of adsorbent injection removing mercury in the flue was carried out in a 0.3 MW coal-fired circulating fluidized bed combustor of pilot scale.The results show that the specific surface area,micropore volume and total pore volume of the adsorbent after modification increase to some extent.The efficiency of injection mercury removal increases with the increase of injection amount and tends to be stable.The mercury removal efficiency increases from 69.36% to 79.44% when the injection amount increases from 0.3 kg/h to 0.5 kg/h.The mercury removal efficiency of the injection process increases with the increase of flue gas temperature,it rose from 57.74% at 142 ℃ to 79.48% at 200 ℃.It is verified that the chemical modified biomass rice husk char is a suitable alternative for activated carbon to be applied into the flue gas injection demercuration technology in coal-fired boilers.