The invention relates to a video monitoring system applicable to a large-span special-structure bridge. The video monitoring system comprises monitoring equipment arranged on a bridge structure and aremote server connected with the monitoring equipment, The monitoring device comprises a fixed-point camera and a mobile camera monitoring subsystem. The fixed-point camera realizes data transmissionwith the remote server through an optical fiber; The mobile camera monitoring subsystem comprises a guide rail, a power supply device and a guide rail type inspection robot carrying a camera; The guide rail type inspection robot realizes data transmission with the remote server through the MESH network transceiver; And the remote server is used for performing action control on the fixed-point camera, the guide rail type inspection robot and the camera carried by the guide rail type inspection robot, acquiring and processing monitoring information and giving an alarm for abnormal conditions. The system achieves the omnibearing monitoring of the bridge structure. While the detection precision is ensured, the labor intensity of personnel is greatly reduced, and the working efficiency is improved.