Ternary Fe2O3-MoS2-Cu2O nanocomposites were fabricated via electrodeposition and hydrothermal method. The as-prepared photocatalytic films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results indicated that MoS2 and Cu2O particles were successfully deposited onto the surface of Fe2O3 particles. MoS2 and Cu2O coloading, achieved a synergetic effect on the improvement of the photoelectrochemical performance of Fe2O3 film. The highest photocurrent density was achieved on Fe2O3-MoS2-Cu2O film, which was 20, similar to 5.5, and 2 times those of Fe2O3, Fe2O3-MoS2, and Fe2O3-Cu2O films, respectively. The excellent photoelectrocatalytic performance was attributed to the Z-scheme electron transfer mechanism, which results in the fast charge transfer and strong redox ability on the ternary composite. This work provides a promising Z-scheme ternary semiconductor for environmental purification and water oxidation.