We report a novel hydrothermal in situ synthesis route for the CdS-sensitized TiO2 nanorod array films and their photoelectrochemical (PEC) performance are investigated in this paper. Although heterojunctions have been well recognized for enhancing the PEC performance of TiO2 nanostructures, the specific synthesis methodology of high production quality, low preparation cost, and high controllability over the heterojunction structures is still a hot and open topic. In this work, controllable nanoscale TiO2/CdS heterojunctions have been successfully realized through hydrothermal synthesis. The absorption spectrum is shown to be broadened from similar to 350 nm to similar to 570 nm, and the photocurrent density increases from 0.35 to 2.03 mA/cm(2), corresponding to photo-conversion efficiency of similar to 0.88%. The method is considered as an efficient and facile choice in the fabrication of TiO2-based PEC hydrogen production functional materials. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.