3D displays become more and more prevalent. Most 3D displays are so complicated and expensive that they are unavailable for ordinary people. Moreover, none of them are interactive. In this paper, we introduce a novel interactive low cost 3D display based on polarized light phenomenon. The system includes a touch box and two mutually perpendicular LCDs with a piece of half-silvered glass which bisects them. This novel system permits: (1) superior quality of display and (2) a novel interactive experience. The principle of the linearly polarized light reflection and refraction is deduced by Fresnel equations. The touch box is used to simulate 3D mouse, which consists of two touch panels. To show how it works, we implemented a 3D game application and a set of interactions are introduced.