The invention relates to a display device and a display system. The display device comprises a frame and a liquid crystal display (LCD) panel arranged in the frame. The LCD panel is provided with a first base plate, a second base plate, and a liquid crystal layer which is placed between the first base plate and the second base plate, a polarizing plate is arranged on one side, deviating from the liquid crystal layer, of the first base plate, and the LCD panel further comprises an analyzing part which is movably arranged on one side, deviating from the liquid crystal layer, of the second base plate. According to the display device, rays of light emitted by backlight become linearly polarized light by polarizing of the polarizing plate, and the linearly polarized light can permeate the liquid crystal layer. When the display device is required to keep confidential, a user needs to wear a pair of polaroid glasses to watch. When the display device is not required to keep confidential, a user can see effective image information on a screen through the analyzing part. Therefore, the display device can be converted between a normal display picture and an abnormal display picture, so that a user is free to choose whether to wear polaroid glasses or not to watch. Thus, the display device has higher usage flexibility.