In this work, we have successfully prepared copper ferrite (CuFe 2 O 4 ) nanoparticles through a modified sol-gel method by of copper (II) nitrate, iron (III) nitrate, and starch as starting materials in water as solvent. The formation of as-produced nanoparticles and their structure, shape and elemental composition were analyzed by means of several techniques including X-ray diffraction, energy dispersive X-ray microanalysis, scanning electron microscopy, and ultraviolet-visible spectroscopy. The magnetic properties of as-prepared copper ferrite nanoparticles were also investigated with vibrating sample magnetometer. In addition, methyl orange was chosen as a dye water pollution to evaluate its degradation by as-synthesized copper ferrite (CuFe 2 O 4 ) nanoparticles under ultraviolet light irradiation. The photocatalysis results reveal that the decolorization of 53 % for methyl orange occurred with CuFe 2 O 4 nanoparticles in 90 min under ultraviolet light irradiation.