A touch screen system includes a touch screen corresponding to a Descartes coordinate system XOY, a first image capturing unit, a second capturing unit, and a processing unit. The first image capturing unit and the second capturing unit are arranged at the periphery of the touch screen and are substantially perpendicular to each other. Both the two image capturing units include a camera and a housing, the camera is housed in the housing to take images, an optical axis of the lens of each camera is perpendicular to X or Y axis of the system XOY respectively for acquiring images including one touch point. The processing unit identifies a touched point on the touch screen and determines X and Y coordinates of the touched point in the system XOY and executing a function corresponding to the X and Y coordinates of the touched point.