A display frame control method, which is applied to an assembled display device in a computer system, the assembled display device at least comprising a graphic controller (251, 252, 253, 254) for outputting image data to a display screen having a resolution of a screen height, H, and screen width, W, in pixels, the graphic controller (251, 252, 253, 254) having a buffer memory, a decoder and an individual screen area zooming module, the display frame control method comprising the steps of: first installing a display frame setup program in the computer system; activating, after the step of installing the display frame setup program, the display frame setup program to acquire a setup command, which comprises information of a specific area of a display frame content corresponding to the image data, wherein the height and/or width of the specific area is smaller than the height, H, and width, W, of the display screen; controlling, after the step of activating the display frame setup program, a graphic driving program (441, 442, 443, 444) to assemble a control signal in order to output the control signal to the graphic controller based on the setup command; and characterized by the further steps, after the step of controlling the graphic driving program, of the graphic controller (251, 252, 253, 254) temporarily storing the image data in the buffer memory; retrieving, by the decoder, the image data from the buffer memory; decoding, by the decoder, the image data into a plurality of original frame data, and temporarily storing the original frame data in the buffer memory; acquiring, by the screen area zooming module, the plurality of original frame data; retrieving, by the screen area zooming module, image data corresponding to the specific area according to the information of the control signal; performing, by the screen area zooming module, a zooming process on the specific area, so that the specific area is enlarged and expanded to the full display screen, thereby transforming the plurality of original frame data to a plurality of target frame data; and temporarily storing the plurality of target frame data and outputting the plurality of target frame data to the display screen. first installing a display frame setup program in the computer system; activating, after the step of installing the display frame setup program, the display frame setup program to acquire a setup command, which comprises information of a specific area of a display frame content corresponding to the image data, wherein the height and/or width of the specific area is smaller than the height, H, and width, W, of the display screen; controlling, after the step of activating the display frame setup program, a graphic driving program (441, 442, 443, 444) to assemble a control signal in order to output the control signal to the graphic controller based on the setup command; and characterized by the further steps, after the step of controlling the graphic driving program, of the graphic controller (251, 252, 253, 254) temporarily storing the image data in the buffer memory; retrieving, by the decoder, the image data from the buffer memory; decoding, by the decoder, the image data into a plurality of original frame data, and temporarily storing the original frame data in the buffer memory; acquiring, by the screen area zooming module, the plurality of original frame data; retrieving, by the screen area zooming module, image data corresponding to the specific area according to the information of the control signal; performing, by the screen area zooming module, a zooming process on the specific area, so that the specific area is enlarged and expanded to the full display screen, thereby transforming the plurality of original frame data to a plurality of target frame data; and temporarily storing the plurality of target frame data and outputting the plurality of target frame data to the display screen. temporarily storing the image data in the buffer memory; retrieving, by the decoder, the image data from the buffer memory; decoding, by the decoder, the image data into a plurality of original frame data, and temporarily storing the original frame data in the buffer memory; acquiring, by the screen area zooming module, the plurality of original frame data; retrieving, by the screen area zooming module, image data corresponding to the specific area according to the information of the control signal; performing, by the screen area zooming module, a zooming process on the specific area, so that the specific area is enlarged and expanded to the full display screen, thereby transforming the plurality of original frame data to a plurality of target frame data; and temporarily storing the plurality of target frame data and outputting the plurality of target frame data to the display screen.