To enhance bridge rapid assessment to ensure the structural safety of the bridge, after the sudden natural disasters. Design camera array underwater detection equipment in order to achieve fast and accurate measurement of the bridge underwater structures disease. In this paper, on the basis of the analysis of the underwater environment, the specific design of the camera array. In order to reduce underwater resistance to adapt in the muddy water close large field of detection, the system uses a camera with lighting miniature endoscope. In order to reduce the pressure of the image mosaic, the system uses the Matrox _morphis_qxt frame grabber, with the RAID disk array system in order to achieve synchronous acquisition, realtime transmission, fast storage.Eventually, through image mosaic technology the apparent closeup view of the measured bridge underwater structures can be restored.