The invention provides a television control device and a correlation method, which are applied to a television system. The television control device comprises a signal source module and a synthesis module, wherein the signal source module is used for obtaining a first frame and a second frame from a first video signal and a second video signal respectively; the synthesis module is used for capturing one part from the first frame to be used as a sub-image when the second frame is displayed on a picture of the television system, and displaying the sub-image to a sub-region of the picture, wherein the sub-image is smaller than the first frame.