Video compression method and device and video transmission system

The invention provides a video compression method and device and a video transmission system. According to the video compression method, a first video signal meeting a preset video format requirement is generated by responding to a received video signal; frame images instructed by image information of each frame in the first video signal are divided into a plurality of subimage blocks carrying image information according to a preset division rule; a compression rule corresponding to each subimage block is determined; then, the image information carried by each subimage block is compressed by utilizing the corresponding compression rule of each subimage block, accordingly, the compression process on the video signal is achieved, and the requirements of the video signal for bandwidth are reduced.