Eu3+-doped　cdWO4　was　prepared　for　the　first　time　by　a　hydrothermal　method.　The　structure,　morphology,　and　luminescence　of　the　Eu　3+-doped　cdWO4　were　characterized.　TEM　results　revealed　that　the　pure　cdWO4　was　a　nanorod　with　a　width　of　about　50　nm.　The　photoluminescent　properties　of　Eu3+-doped　cdWO4　complexes　indicated　energy　transfer　from　WO42-　groups　to　Eu　3+　and　suggested　effective　doping　of　Eu3+　into　the　lattice　of　cdWO4.　The　photocatalytic　activity　of　cdWO4　and　Eu3+-doped　cdWO4　was　investigated　by　the　photodegradation　of　methyl　orange　(MO).　Eu3+-doped　cdWO4　had　enhanced　photocatalytic　activity　in　the　photodegradation　of　MO.　The　hydroxyl　radical　was　detected　by　the　terephthalic　acid　photoluminescence　(TA-PL)　method,　and　the　regular　change　revealed　that　the　hydroxyl　radical　may　be　the　active　species.　©　Springer　Science+Business　Media　B.V.　2009.