Transparent and flexible applications have captured extensive attention recently due to the intriguing functionalities and great potential influencing our daily life. In addition, with the increasing demand for green energy, photoelectrochemical (PEC) water splitting, which is a clean process directly converting solar energy to chemical energy in the form of hydrogen, becomes much emphasized worldwide. In this work, we combine these two popular trends to develop a transparent and flexible PEC photoelectrode. We use pulsed laser deposition process to fabricate heterostructural SrTiO₃/ZnO bilayer on flexible muscovite substrate. ZnO is a well-known material for PEC water splitting due to its good photoactivity and suitable band gap across the redox potential of water. SrTiO₃ also has photocatalytic ability and highly photochemical stability as the surface protection oxide to enhance the retention of PEC performance. This combination not only shows good transmittance in visible light region but also exhibits superior performance on PEC activity. Furthermore, the photocurrent of SrTiO₃/ZnO heterostructure under different bending condition is investigated. This study first demonstrates a pathway to flexible and transparent photoelectrode for developing innovative PEC devices on water splitting.