Grafting one-dimensional semiconductor nanostructures inside arrayed nanotubes of another semiconductor to form network heteroarchitectures is believed to improve photocatalytic activity on the bases of an enhanced separation of photoexcited electron-hole pairs and an enlarged surface area for light absorption and chemical reactions. Thus in this study, single-crystalline ZnO nanorod grafted anatase TiO₂ nanotube three-dimensional arrayed heterostructures were synthesized via a simple solution process and acted as supporting platforms for nanoparticle deposition. The lattice orientations of the ZnO nanorods and TiO₂ nanotubes were examined and suggested that the rods heterogeneously nucleated on the tubes and grew along a [002] direction following a structural correlation ZnO (100)//TiO₂ (103). Silver nanoparticles were further deposited on the platforms to compose TiO₂/ZnO/Ag multi-junction heterostructures which exhibited much superior photocatalytic activity than a conventional TiO₂ nanotube array did.