The urea has been used as a precipitant agent to react with soluble Zn2+2+ salt and Eu3+3+ salt for preparing ZnO:Eu3+3+ nanocrystals. The particle size, the crystal structure and morphology of the nan ocrystalline ZnO:Eu3+3+ were characterized by x-ray diffractio n and transmission electron micrograph. Narrow-sized, finely dispersed nanocrys talline ZnO:Eu3+3+ with a small size about 8nm has been obtained by homogeneous precipitation method. By using different preparation methods, obtai ning different dimensions of crystals with different doping concentrations, the luminescence characteristics of nanocrystalline ZnO:Eu3+3+ were stu died. The results indicate that the homogeneous precipitation method is a kind o f superior preparation technique for nano-size doped materials, and also demons trate the feasibility of nanocrystalline ZnO:Eu3+3+ for luminescent applications.