The objective of this research was to prepare multi–phase bismuth vanadate (BiVO4) powder using the solvothermal method to be used as a photocatalyst. In the preparation step, bismuth nitrate and ammonium vanadate were used as the precursors with a mole ratio of 1:1. The mixed solution was diluted to 0.025 M with acetic acid and heated at 200 °C for 2 h in a Teflon–lined stainless steel autoclave vessel. Multi–phase BiVO4was obtained without calcination step. Multi–phase BiVO4was characterized by X–ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT–IR), and energy dispersive spectroscopy (EDS). The efficiency of multi–phase BiVO4for photocatalytic degradation of the mixed dye of methylene blue (MB) and rhodamine B (RhB) solution under UV light irradiation was studied. The concentration of the mixed dye solution was measured by UV–Vis spectrophotometry (UV–Vis). The effect of concentration of catalyst and pH of solution was studied. The optimum conditions for photocatalytic degradation of mixed dye solution were obtained at 0.8 g/L for concentration of multi–phase BiVO4and 7.78 for initial pH of the mixed dye solution.