Cu-TiO2 heterostructure nanoparticles were successfully synthesized via a novel one-step self-assemble hydrothermal method using polyethylene glycol as the soft template. The nanospheres were characterized in light of the chemical composition and morphology using X-ray diffraction (XRD) and transmission electron microscope (TEM), respectively. The products are composed of cubic copper and anatase TiO2. Interfaces between Cu (101) and TiO2 (111) were observed by HRTEM. In addition, the nanoparticles size could be controlled by adjusting the polymerization degrees of PEG. The accommodations of the particle sizes were mainly caused by Cu nanospheres rather than TiO2. A possible synthetic mechanism which interprets the formation of Cu-TiO2 heterogeneous nanoparticles could be ascribed to the hydrogen bonds between Cu(NH3)2+ and PEG. UV-Vis absorption spectra indicated that the prepared product has strong absorbency in the visible region. Therefore, the unique interface nanomaterial could be used as a potential class of the materials platform as visible-light-driven photocatalyst and electrode on enhancing the photoelectric properties of solar cells.