One dimensional core/shell nanostructures consisting of two different semiconductors with appropriate band alignment are promising for photocatalytic hydrogen production due to their efficient light harvesting and fast carrier transport. In this work, CdS/ZnO core/shell nanofibers were successfully synthesized by one-pot single-spinneret electrospinning. The ZnO layered structures (60 nm in thickness) were uniformly grown onto continuous CdS core fibers (220 nm in diameter and several micrometers in length). The as-fabricated CdS/ZnO core/shell nanofibers as nanoheterojunction photocatalysts exhibited excellent visible light photocatalytic activity and stability for hydrogen production. The possible formation mechanism of the CdS/ZnO core/shell nanofibers was also proposed based on the experimental observations. Moreover, the morphologies and components of the as-prepared nanofibers can be controlled easily by tuning the annealing temperature and Zn/Cd ratios of the precursor solution.