The invention discloses a method for improving compression property of video sequence with unchangeable background, in particular a method for reducing part of code stream of the background part for YUV format video images with unchangeable background during the transmission. The method comprises the following steps: firstly, obtaining video image sequences which are 1/16 of video sequence images to be compressed; secondly, analyzing the difference value of Y of two adjacent frames in the video image sequences; thirdly, finding and removing choppy points of the Y values. The method analyzes in the video images which are shortened by 16 times, can reduce the calculated amount, avoid the insignificant mutation of the Y values of part of the background part and omit the mutated code transmission during the transmission of the video sequences with unchangeable background, and only needs to transmit one-time codes of the background part, thereby greatly reducing the code stream.