The　interactions　between　DNA　and　small　molecules　with　planar　heterocyclic　structure　were　indicated　in　previous　researches.　This　study　investigated　the　interactions　between　PFOS　with　linear　chain　structure　and　DNA.　A　new　phenomenon　of　DNA　damage　due　to　PFOS　using　electrochemistry　technique　was　proved.　The　data　was　obtained　on　a　modified　glassy　carbon　electrode,　on　which　didodecyldimethylammonium　bromide　(DDAB),　ZrO2　and　calf　thymus　DNA　were　immobilized　layer-by-layer.　Electrochemical　response　of　DNA　damage　caused　by　PFOS　was　detected　by　differential　pulse　voltammetry　(DPV)　using　methylene　blue　(MB)　as　electro-active　indicator.　The　current　of　MB　attenuated　obviously　after　DNA/ZrO2/DDAB/GCE　were　incubated　in　PFOS.　The　shift　of　MB　reduction　peak　potential　indicates　that　PFOS　is　bound　with　DNA　in　groove　probably　by　the　first　step　of　hydrophobic　interaction　and　then　the　second　step　of　intercalation　into　the　base　of　DNA.　X-ray　photoelectron　spectroscopic　(XPS)　was　used　to　elucidate　in　detail　the　intercalation　of　PFOS　into　DNA　and　the　formation　of　hydrogen　bond　between　PFOS　and　DNA　base.　Electrochemical　quartz　crystal　microbalance　(EQCM)　proved　the　formation　of　adducts　of　DNA　and　PFOS.　Moreover,　electrochemical　impedance　spectroscopy　(EIS)　indicates　that　the　PFOS　influence　DNA　structure　and　attenuate　DNA　charge　transport.　These　results　demonstrate　that　PFOS　intercalated　into　DNA　do　induce　DNA　base　damage.　(C)　2012　Elsevier　By.　All　rights　reserved.