Abstract: Theory and method of reconstruction of digital holographic microscopy are discussed. A magnified image of USAF1950 is recorded with off-axis digital holographic setup. The holograms are numerically reconstructed in amplitude and phase distribution. The digital reconstruction algorithm based on Fresnel diffraction is analyzed and applied. The modeling of digital reference wave for digital reconstruction, the removing of the zero-order and the twin images by frequency filter and reconstruction parameters are solved. A focused image of the specimen is reconstructed to show that this technology can be used in phase-contrast measurements of micro-object.