A ternary nanocomposite photoelectrode composed of cadmium sulfide (CdS), polyaniline (PANI), and bismuth vanadate (BiVO4) was successfully designed by combining cyclic voltammetry (CV) with electrochemical deposition and high-temperature calcination. The first synthesized CdS/PANI/BiVO4 composite was used as a photoelectrochemical (PEC) monitoring platform for glutathione (GSH). The ternary CdS/PANI/BiVO4 nanocomposites exhibited higher PEC activity, which was attributed to the accelerated electron transfer by the loading of CdS and PANI, which enables the material surface to better adsorb the electrons separated by GSH, thereby oxidizing it into GSSH. The photoanodes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy, and photoelectrochemical experiments. Under the optimal experimental conditions, the BiVO4 electrode modified with CdS and PANI exhibited a linear response in the concentration range of 0.1-20 μM with a sensitivity of 0.669 μA mM-1 cm-2 and a detection limit of 40 nM. Moreover, the PEC sensor exhibits good reproducibility and long-term stability. In summary, the designed materials have excellent electrochemical properties, which make them ideal candidates for PEC detection of GSH.