Abstract: In the determination of electron diffraction pattern of crystal involving interface, dislocation and other defects of crystallography properties, to eliminate the problem of 180° nonuniqueness is needed. In this article, using the precise specimen stage of transmission electron microscope (FEI, Tecnai G² F20) the systematic tilting of crystals can be accomplished, and by the analysis and study of the changes of electron diffraction pattern, the selection of the right index of crystalline plane and index of zone axis, the elimination of 180° nonuniqueness of ZnO diffraction pattern can be achieved.