When the stripes are photographed by digital cameras,Moiré fringes will be in the photograph. With the displacement amplification of Moiré fringes, tiny movement of stripes can be calculated precisely. We expounded its calculating methods in this paper. Experimental data show that high precision can be guaranteed. It is well known that the high rate zoom characteristic of moire fringe technique can be well used in precise measurement of digital Camera’s displacement, and besides, widely used in machining, laboratory and photo-electricity equipment. With the development and popularization of digital cameras, especially the great advancement in image sensor’s performance, it now becomes possible to accurately measure the displacement from far away by taking into account the sensor’s moire effect.