Fragile digital watermarking is one of the methods used for authentication of surveillance video. A fragile digital watermarking scheme is proposed, in which the watermark is made up of time information and camera ID, the secret key is generated based on the video feature, the watermark is embedded into the chromatism component of B frames. This watermarking scheme can detect and locate the modification of the video, including frame cut, foreign frame insertion and frame swapping etc. In addition, while the video is played back, the watermark information picked up from the carrier can be displayed on the video, which is a replacement of the traditional OSD (On Screen Display).