A positioning rack module for supporting a computer at a backside of a display device includes a movable frame. The movable frame includes a movable frame body to be disposed at the backside of the display device, and a first receiving portion formed in the movable frame body for receiving the computer. The movable frame body is operable to move relative to the display device between a hidden position and an exposed position. The movable frame body is hidden behind the backside of the display device when disposed at the hidden position. The movable frame body extends beyond a lateral side of the display device when disposed at the exposed position.