Traditional discrete monitoring system of train cabin used a number of independent cameras to monitor different parts inside. This monitoring method had narrow vision and different perspectives and staff members had to switch back and forth between multiple monitoring screens to find and judge the cause when there were sudden events.A panoramic monitoring scheme based on multi-camera video mosaic technology was proposed, which was the mosaic algorithm combining PCA-SURF and improved BBF. The index table was used to stitch video frame sequences from cameras in real time. The experimental results in laboratory environment showed that the proposed algorithm could reduce the time of single frame splicing by 90% compared with the traditional SURF algorithm,the correct matching rate reaching 92.2%, the proposed algorithm worked well in splicing speed and quality.