Expensive and cumbersome 3D equipment currently limits the popularization of emerging stereo media on the Internet. Particularly for stereo images, as a major kind of stereo media widespread on the Internet, there is not yet a good solution to show stereoscopy in conventional display. By investigating the principles of human visual system (HVS), this paper proposes a method, called Flat3D for animating stereoscopy only through a conventional screen (2D) based on the motion parallax. The way for exhibition is dynamically transforming consistent views from left to right and then playing back reversely. The relative motion impresses viewers with strong depth perception. We investigate some factors which affect viewing experience in Flat3D and find that a reasonable fixation point and structure-preserved view transition contribute the most. Based on the above findings, we develop an adaptive fixation acquisition approach combining color and depth cues, as well as employing a probabili...