An apparatus for adjusting a displayed picture, comprising a video signal input means (11, 1, 6), a position measuring means, an image processing means (13, 3, 7, 9) and a video signal output means (12, 4, 8), wherein the video signal input means (11, 1, 6), the position measuring means and the video signal output means (12, 4, 8) are all connected to the image processing means (13, 3, 7, 9); the video signal input means (11, 1, 6) is used for transmitting an acquired video signal to the image processing means (13, 3, 7, 9); the position measuring means transmits position information of a viewer with respect to a display screen collected before and after a change in position of the viewer; the apparatus further comprising: an eye tracker for detecting information of position being gazed by eyes on the display screen and transmitting the information of position being gazed to the image processing means (13, 3, 7, 9), the image processing means (13, 3, 7, 9) adjusts the video signal according to the position information before and after the change in position of the viewer to enlarge a partial image at the position being gazed in the video signal, and transmits the adjusted video signal to the video signal output means (12, 4, 8), the image processing means (13, 3, 7, 9) further comprises: an image enlarging module (131, 32) for enlarging a partial image at the position being gazed in the video signal according to the position information before and after the change in position of the viewer and transmitting a picture having the partial image enlarged to a video signal generating module; and the video signal generating module for generating a new video signal according to the picture having the partial image enlarged and transmitting the new video signal to the video signal output means (12, 4, 8); characterized in that: the image processing means (13, 3, 7, 9) further comprises: an image restoring module for receiving the video signal input from the video signal input means (11, 1, 6), judging a similarity between pictures of two adjacent frames in real time, and transmitting a signal indicating stopping enlarging to the image enlarging module (131, 32) when the similarity is lower than a predetermined threshold, and the image enlarging module transmits the video signal to the video signal output means (12, 4, 8) directly as it was acquired. an eye tracker for detecting information of position being gazed by eyes on the display screen and transmitting the information of position being gazed to the image processing means (13, 3, 7, 9), the image processing means (13, 3, 7, 9) adjusts the video signal according to the position information before and after the change in position of the viewer to enlarge a partial image at the position being gazed in the video signal, and transmits the adjusted video signal to the video signal output means (12, 4, 8), the image processing means (13, 3, 7, 9) further comprises: an image enlarging module (131, 32) for enlarging a partial image at the position being gazed in the video signal according to the position information before and after the change in position of the viewer and transmitting a picture having the partial image enlarged to a video signal generating module; and the video signal generating module for generating a new video signal according to the picture having the partial image enlarged and transmitting the new video signal to the video signal output means (12, 4, 8); an image enlarging module (131, 32) for enlarging a partial image at the position being gazed in the video signal according to the position information before and after the change in position of the viewer and transmitting a picture having the partial image enlarged to a video signal generating module; and the video signal generating module for generating a new video signal according to the picture having the partial image enlarged and transmitting the new video signal to the video signal output means (12, 4, 8); characterized in that: the image processing means (13, 3, 7, 9) further comprises: an image restoring module for receiving the video signal input from the video signal input means (11, 1, 6), judging a similarity between pictures of two adjacent frames in real time, and transmitting a signal indicating stopping enlarging to the image enlarging module (131, 32) when the similarity is lower than a predetermined threshold, and the image enlarging module transmits the video signal to the video signal output means (12, 4, 8) directly as it was acquired.