In order to compare the bromate removal effect of activated carbon with that of biological activated carbon,by making pilot-scale test,the changes of biomass on activated carbon surface and bromate removal rate were investigated. The results indicated that the bromate removal rate of new activated carbon was 57. 1% ,and as the biomass increased,the removal effect of bromate was improved gradually during transformation process from granular activated carbon to biological activated carbon. After 8 months,the bromate removal rate achieved 75. 4% and the concentration of bromate could be controlled by biological activated carbon steadily,which proved that biological activated carbon was more suitable for bromate removal than granular activated carbon.