The composition of a photocatalyst is the fundamental determinant of its photoability. Recently, significant attention has been focused on the ternary oxide epitaxial overlayers. Here, a highly active {001} facet dominant coaxial-nanocoupled SrTiO3/TiO2 nanotube array thin film was fabricated by a modified two-step anodization combined with a hydrothermal process. Through photoelectrochemical (PEC) measurements, such a coaxial-nanocoupled SrTiO3/TiO2 {001} surface reconstruction can definitely improve its PEC performance. The enhanced PEC performance and strongest photocurrent response of SrTiO3/TiO2 nanotubes (STNs) with a 2 h hydrothermal treatment were ascribed to the fast electron transfer in coaxial nanoarchitecture.