A series of these novel CuO(x)/LaFeO3 (x = 0-100%) nanocomposite photocatalysts were successfully fabricated by the sol-gel method. The obtained nanoparticles were characterized by several analysis techniques such as XRD, FT-IR, UV-Vis DRS, photoluminescence, TEM and EDS for identifying their structural, physical and optical characteristics. The photocatalytic activities of CuO(x)/LaFeO3 nanoparticles were examined by photo degradation of Rhodamine B (RhB) under the visible light irradiation. The most improvement was achieved in the photocatalytic activity of the CuO(50%)/LaFeO3 nanocomposite compared to those of the pure LaFeO3 and other composites. It was interesting that addition of a low amount of H2O2 (0.5 mL) greatly improved the photocatalytic performance so that a 6 ppm RhB was degraded only in dark (after 60 min without light illumination) and high concentration of RhB (30 ppm) was removed after 90 min. Furthermore, a 20 ppm phenol contaminant was destroyed after 150 min using the CuO(50%)/LaFeO3 in presence of H2O2. These outstanding results could be ascribed to the simultaneous effects of the photocatalysis and Fenton-like mechanism that enhanced the photocatalytic efficiency. It was proposed that the non-toxic, inexpensive, highly active and stable CuO(50%)/LaFeO3 nanocomposite photocatalyst have the potential to be used in practical industrial water treatment processes under the visible light illumination.