Abstract: The polychlorinated biphenyls (PCBs) in indoor and outdoor dust around the traffic road in Hunan Province were sampled and detected. The ∑PCBs in indoor dust ranged from 156-507ng/g, with a median of 362ng/g, and the ∑PCBs in outdoor dust ranged from 106-955ng/g, with a median of 406ng/g. Similar pattern of PCBs was observed in indoor and outdoor dust, which was dominated by Penta-PCBs and Hexa-PCBs. Risk assessment showed that cancer risk of human exposure to PCBs via dust varied from 1.28-2.97×10-7, with a median of 2.31×10-7, when the high slope factor was employed, and the risk ranged from 6.38×10-8-1.49×10-7, with a median of 1.16×10-7，when the central slope factor was employed. All of the risk values were below the acceptable risk level (1×10-6), which may indicate the relative safety of the present environment.