A method for eliminating wavefront aberration, used in phase difference amplification was proposed. Two holograms were inserted in two optical paths of a Mach-Zehnder interferometer respectively. One of the holograms recorded the information of both object phase and wave-front aberration of the system, the other recorded only that of wavefront abarration. While reconstructing, the wayefront abarratioa could be eliminated and the amplified phase difference obtained. The experimental results were given finally.