We　reported　a　facile　hydrothermal　route　for　the　preparation　of　WO3-TiO2　composite　nanoparticles　(TWCNs)　using　waste　WC-TiC　hardmetal　in　the　presence　of　hydrofluoric　acid　(HF).　Scanning　electron　microscopy　(SEM),　transmission　electron　microscopy　(TEM),　X-ray　diffraction　(XRD)　and　nitrogen　adsorption/desorption　analysis　were　employed　for　structural　and　composition　analyses　of　the　TWCNs.　Our　results　suggested　that　HF　was　not　only　strongly　involved　in　the　growth　of　WO3,　but　also　played　a　critical　role　in　the　etching　effect　for　TWCN　product.　The　photocatalytic　activity　of　TWCNs　was　investigated　by　UV-vis　spectroscopy.　Dye　molecules　could　be　rapidly　decomposed　with　TWCNs　photocatalyst　under　visible　light　illumination.　The　enhanced　photocatalytic　activity　is　attributed　to　well　matched　band　edge　positions　of　WO3　and　TiO2,　and　the　large　specific　surface　area　of　TWCNs　in　view　of　the　incorporation　of　mesopores.　The　results　presented　here　are　expected　to　make　a　contribution　toward　the　development　of　recycling　waste　resource　delicately　for　photocatalytic　water　purification.