In this study, Bi 2S 3 sensitive layer has been grown on the surface of WO 3 nanoplate arrays via an in situ approach. The characterization of samples were carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and ultraviolet–visible absorption spectroscopy (UV-vis). The results show that the Bi 2S 3 layer is uniformly formed on the surface of WO 3 nanoplates and less interfacial defects were observed in the interface between the Bi 2S 3 and WO 3. More importantly, the Bi 2S 3/WO 3 films as photoanodes for photoelectrochemical (PEC) cells display the enhanced PEC performance compared with the Bi 2S 3/WO 3 films prepared by a sequential ionic layer adsorption reaction (SILAR) method. In order to understand the reason for the enhanced PEC properties, the electron transport properties of the photoelectrodes were studied by using the transient photocurrent spectroscopy and intensity modulated photocurrent spectroscopy (IMPS). The Bi 2S 3/WO 3 films prepared via an in situ approach have a greater transient time constant and higher electron transit rate. This is most likely due to less interfacial defects for the Bi 2S 3/WO 3 films prepared via an in situ approach, resulting in a lower resistance and faster carrier transport in the interface between WO 3 and Bi 2S 3.