In this research, self-assembled copper sulfide nanospheres were synthesized by the solvothermal method and the effects of reaction parameters, including reaction time and reaction temperature on the morphology and phase evolution of copper sulfide nanostructures were investigated. For the identification of copper sulfide nanostructures, X-ray diffraction (XRD), infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), and elemental analysis (EDX) were used. The results showed that the temperature of 200 °C for 24 h is sufficient for the formation of the pure hexagonal Cu7.2S4 phase. The Cu7.2S4 nanostructures have a spherical morphology that formed from the self-assembly of the nanoparticles. Finally, the photocatalyst efficiency of Cu7.2S4 sphere was investigated.