To investigate the effects of different packing modes, inoculation quantites and hydraulic retention time on nitrate removal, permeable reactive barriers (PRBs) packed with sawdust, zero-valent iron (Fe0) and active carbon were tested in laboratory. The PRB filled with completely mixed sawdust and Fe0 showed higher nitrate removal efficiencies than those filled with sawdust and Fe0 in layer modes. Nitrate removal efficiencies and dissolved organic carbon (DOC) in effluent increased with hydraulic retention time increased. Within limits, increasing the amount of inoculum quantity of PRB could increase nitrate removal rate. Nitrate removal efficiency, DOC concentration and the number of bacterial colonies in effluent decreased with the initial nitrate concentration increasing, whereas the accumulation of ammonium showed an opposite trend. Addition of active carbon not only could promote the reduction of nitrate, decrease ammonium concentration but also could improve outlet water chroma. Furthermore, the nitrite could be nearly detected in the effluent, while the number of bacrteria colonies changed from 103 CFU/mL to 106 CFU/mL. 