Pollution characteristics,bioaccumulation and potent ial health risk of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were preliminarily studied in typical farmland soil-ecosystems of Yangtze River Delta region.The results showed that averaged concentration and TEQ of total PCDD/Fs in the farmland soil were 556 pg g^-1dw and TEQ 2012 pg g^-1 dw.The bioaccumulation of PCDD/Fs was clearly observed in different biological tissues.The concentration and TEQ of PCDD/Fs were 5017 pg g^-1 dw and TEQ 614 pg g^-1 dw in the rice,3512 pg g^-1 dw and TEQ 617 pg g^-1 dw in the stems and leaves of vegetables,3019 pg g^-1 ww and TEQ 517 pg g^-1 ww in the chicken meat.The tolerable daily intake(TDI) values estimated based on the following exposure ways of rice-vegetable,rice-vegetable-Houttuynla cordata Thunb,rice-vegetable-Hout-tuynla cordata Thunb-chicken meat were TEQ 6714,7211,8315 pg kg^-1d^-1,respectively,which all were higher than the tolerable daily intake(TDI) (TEQ 1~4 pg kg^-1 d^-1) for PCDD/Fs recommended by the World Health Organization(WHO).It is concluded that bioaccumulation of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs) from the farmland ecosystems has posed potential risks to agro-product safety and human health in the typical contaminated area.