A method, system, and related device for operating a display device are disclosed. The method includes: a control device transmitting the directional light to the display device when detecting a key thereof is pressed, and transmitting the collected intensity data of the first reflected light and the key information to a light tracking system; the light tracking system matching a corresponding coordinate position according to the received intensity data of the first reflected light and the known current distance between the control device and the display device, from the preconfigured reflected light intensity corresponding to the distances between the control device and the coordinate positions of various directional points on display device at the distance, then executing a corresponding operation on an area of the display device corresponding to the coordinate position in conjunction with the key information, and reflecting an operation result on the display device.