The invention discloses an automatic butt-joint method and device suitable for a wharf oil conveying pipe loading and unloading arm and a ship flange. The method is characterized in that a positioningdevice is utilized and comprises a laser positioning device and a vision positioning device, primary positioning and precise positioning are conducted on the oil conveying pipe loading and unloadingarm and a ship target flange, a drive control system is used for controlling a horizontal drive device, an outer arm drive device and an inner arm drive device which are arranged on the oil conveyingpipe loading and unloading arm, and the drive arm moves till a hydraulic drive rapid connector and the ship target flange are in accurate butt joint. A set of CCD cameras are arranged in the vision positioning device to monitor the position of an oil conveying port in real time, a processing module in the vision positioning device outputs coordinate signals to the drive control system, accordingly, the hydraulic drive rapid connector of the oil conveying pipe arm and the target flange are driven to be in accurate butt joint, and the butt joint precision is improved; and it is guaranteed that oil liquid cannot leak, the problem of environment pollution is solved, the requirement for large-tonnage wharf work is met, and economic benefits are greatly increased.