It is well known that, due to their specific properties, ZnO - based materials are frequently used in electrotechnics and electronics. Since these properties are very Much dependent on the microstructural state of material (grain size, pore size, grain and pore distribution), in this article systematic investigation of evolution of microstructural constituents occurred during sintering of ZnO has been performed by new digital pattern recognition method (DPR). Microstructure investigations of the influence of the sintering regime on microstuctural development of ZnO ceramics were carried out, using the scanning electron microscope (SEM) digital pictures, their contour recognition and decomposition of digital image objects according to their gray scale intensity (automatic microstructural analysis). The obtained results enable to establish the sintering parameters, which are indispensable for processing of materials with advanced required properties.