A g-C3N4/BiVO4 composite photocatalyst with enhanced photocatalytic activity and photoelectrochemical (PEC) performance was fabricated via a simple synthesis method with BiVO4 nanofibers as starting material. The materials were characterized with different techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), Fourier transform infrared spectroscopy (FT-IR), N2 absorption–desorption isotherm (BET) and photoluminescence spectroscopy (PL). The results showed that this synthesis method is effective to make a composite. The photocatalytic evaluation indicates that the photocatalytic activity of the g-C3N4/BiVO4 photocatalyst for methylene blue (MB) was about 8 and 7 times higher than that of pure BiVO4 and g-C3N4, respectively. This should be due to the enhanced light harvesting ability and to the effective electron transfer during the photocatalytic reaction.