The interfacial bonding utilizing Ag2O-derived silver nanoparticles was evaluated using TEM observation and molecular dynamics simulation. The TEM observation reveals that the crystal orientation of the sintered silver corresponded to that of the gold substrate. This is considered that the epitaxial layer of silver was formed through in-situ formation of silver nanoparticles from Ag2O paste, and oriented in the direction of the gold crystal. MD simulation successfully recreated the sintering behavior of silver nanoparticles and the gold substrate. The simulation results clearly showed the epitaxial layers of silver atoms were formed on the substrate. The existence of the closed pore indicates the acceleration of the sintering between nanoparticles and the gold substrate to minimize the total sum of surface energy and grain boundary energy.