The invention discloses a comprehensive bridge detection device comprising a cross rail, longitudinal rails, a rail car, an onboard unit and a monitoring system. The longitudinal rails are used for being fixed to a bridge or accessory structures of the bridge, the cross rail is used for being arranged on the longitudinal rails and capable of moving along the longitudinal rails, the rail car is used for being arranged on the cross rail and capable of moving along the same, the onboard unit is used for being mounted on the rail car and comprises a camera device, and the monitoring system comprises a communication subsystem, a control subsystem and a testing subsystem. The communication subsystem is used for realizing communication between the rail car and the onboard unit, the control subsystem is used for controlling moving and positioning of the cross rail, the rail car and the onboard unit, and the testing subsystem is sued for detecting states of the bridge according to bridge pictures which are shot by the camera device. The comprehensive bridge detection device has the advantages of low cost, high efficiency, reliable performance and the like, and can support detection of multiple indexes such as bridge cracks, bearings, deflection or inclination.