The invention discloses a BIM-based multi-source detection system and detection method of an operating bridge. On the basis of the BIM technology, the unmanned aerial vehicle and the three-dimensionallaser detection technology are integrated into the bridge disease detection, so that the bridge inspection efficiency and precision are improved greatly. An image processing method based on a sub-pixel difference is proposed, so that a defect of poor precision of the existing hardware equipment is overcome to a certain extent. Therefore, the bridge operation and maintenance inspection efficiencyare improved substantially; the informationization and intelligence degrees of the operation and maintenance decision-making system of the bridge are increased; and thus operation and maintenance decision-making of the bridge becomes scientific.