An image processing system, for processing display data and vertical blanking interval data carried by a composite signal, is disclosed. The image process system includes: a video decoder, for decoding the display data to generate corresponding image data; a VBI decoder, for decoding the VBI data to generate corresponding VBI image data; a converter, for converting the VBI image data into color index data; a transmission interface, for transmitting the decoded image data and color index data; and an image processing module, for receiving the image data and the color index data to deinterlace/scale the image data and converting the color index data back into the original VBI image data, mixing the processed image data and the VBI image data such that data to be displayed can be generated.