In this study, mangrove (Kandelia candel) seedlings were planted in sediments contaminated with a series of concentrations of PCB47（2,2′,4,4′-tetrachlorobiphenyl）and PCB155（ 2,2′,4,4′,6,6′, - hexachlorophenyl）. The ability and mechanisms of Kandelia candel to remediate PCB47 and PCB155 were studied. At the end of a 180-day experiment, the residual concentrations of PCB47 and PCB155 were lower in the sediments planted with Kandelia candel than in non-planted sediments. The residual concentrations of PCB47 and PCB155 in planted sediments were 53.99-528.37μg?kg-1 and 68.25-682.90μg?kg-1, respectively，which were 10.40%-15.46% and 6.10%-11.94% lower than control 1 (with addition of HgCl2 ), and 7.70%-12.85% and 5.28%-8.27% lower than control 2 (without HgCl2 ). Kandelia candel could take up PCBs from the sediments, and generally took up more PCBs when PCB concentrations were higher. The concentrations of PCB47 and PCB155 in Kandelia candel were highest in the root, followed by the leaves, and lowest in the shoot. The accumulation of PCBs in Kandelia candel leaves was from two pathways. Root uptake and transport to the leaves was the main uptake pathway in the sediments with higher level concentrations of PCB47 and PCB155. Volatilization from soil and uptake by aerial plant part was the main uptake pathway in the sediments with lower level concentration of PCB47 and PCB155; Root bioconcentration factors (BCFs) of Kandelia candel for PCB47 and PCB155 tended to decrease with increasing concentrations of the contaminants in sediment, and the BCFs for PCB47 were larger than those for PCB155. The BCFs for PCB47 and PCB155 in Kandelia candel was highest in the root, followed by the leaves, and lowest in the shoot. Results from this experiment indicated that removal of PCBs from contaminated sediments by mangrove species Kandelia candel may be a feasible approach to sediment remediation.