The surface of PMNPT relaxor ferroelectric single crystal was coated with medium and high temperature Ag paste by screen printing process. Ag electrodes were prepared by rapid sintering process at 650 and 850 ℃, respectively. The microstructure of Ag electrode surface and metalcrystal interface was observed by scanning electron microscope. The distribution of elements at the interface was analyzed by energy spectrum. The Ag electrode has a thickness of tens of microns, a porous structure, and a good combination with crystals. After sintering, atoms such as Pb, Nb and Ti in the crystal migrate to the Ag electrode, and a transition layer of several microns thickness is formed at the interface after sintering of the high temperature Ag paste, which greatly reduces the migration of atoms in the crystal to the electrode. PMNPT wafers with different crystal orientation have a strong crystal face effect during the diffusion process to the Ag electrode at high temperature, and the diffusion degree of Pb, Nb and Ti atoms in the ［110］ direction crystal is smaller than that in the ［100］ direction crystal.