Cu2O nanocubes and Cu nanoparticles were prepared by reducing Cu(Ⅱ) salt with ethanol as the reducing agent and solvent in the presence of multidentate ligand poly(vinylpyrrolidone) (PVP) under different conditions. The morphologies and the crystalline structures of the products were characterized by using scanning electron microscopy (SEM), transmission electron microscopy(TEM), selected-area electron diffraction(SAED), and powder X-ray diffraction(XRD). In particular, the influences of the solvothermal reaction temperature and alkalinity on the products were investigated. A lower temperature and a lower alkali concentration favor the formation of the Cu2O phase, whereas a higher temperature and a higher alkali concentration generally lead to the formation of the Cu phase.