PTFE　fiber　was　grafted　with　acrylic　acid,　and　then　the　resulting　grafted　PTFE　fiber　reacted　with　ferric　chloride　to　prepare　a　Fe　modified　PTFE　fiber,　which　was　used　then　as　the　heterogeneous　photo-Fenton　catalyst　for　the　oxidative　degradation　of　the　water-soluble　anionic　azo　dyes　with　different　strucatures　in　water.　Effect　of　Fe　content,　the　solution　pH　and　dye　structure　characteristics　on　dye　degradation　was　examined　with　respect　to　the　decoloration　percentage　under　different　light　irradiations.　Photocatalytic　degradation　procedure　of　azo　dye　was　also　investigated　by　using　UV-Visible　spectrum　and　TOC　measurement　in　this　work.　The　results　indicated　that　Fe　modified　PTFE　fiber　showed　a　better　catalytic　performance　on　azo　dye　degradation　under　light　irradiations,　especially　UV　light,　which　led　to　the　decomposition　and　mineralization　of　dye　molecules.　Increasing　Fe　content　would　significantly　accelerate　dye　degradation.　Fe　modified　PTFE　fiber　has　the　high　photocatalytic　activity　at　pH≤6.0　solution,　however,　its　activity　was　reduced　unsignificantly　at　alkaline　medium.　In　addition,　the　photocatalytic　degradation　of　azo　dyes　was　determined　by　the　numbers　of　azo　linkages　in　their　molecules　in　the　presence　of　Fe　modified　PTFE　fiber.