The cu-doped ZnO nano-particles were prepared by sol-gel method. The structure of the samples was investigated through X-ray diffraction, and their Raman scatting spectra. The XRD analysis indicated that cu-doped into the lattice of ZnO, while the ZnO wurtzite structure is not changed. The samples were nano-polycrystal. The cu atoms were located in ZnO lattice as substitutional atoms. The crystallization degree of the cu doped ZnO nano-particles is related with calcination temperature. The optimized temperature is 600 ℃in our experiments. Room-temperature Raman spectrum revealed that the cu-doped ZnO nano-particle has the same lattice vibrational modes as those of pure ZnO, suchas A₁, B₁, E₁, E₂, etc. With the increasing of cu-doping concentration, the lattice distorted, and stress in crystal strengthened and point defects increased. The peaks in Raman spectrum broadened and the intensity of the peaks decreased which show that. The size of crystal grains reduced as the cu-doping concentration increased. In lattice of the cudoped ZnO nano-particles, there may be also some Raman inactive modes which can't be reflected in Raman spectrum.