A hydraulic location device for guiding a ship in a floating dock and a working method thereof belong to the technical field of ship maintenance and modification and oceaneering equipment. The ship guiding location device with a hydraulic location function is composed of a plane steel frame, a rubber wheel, a hydraulic cylinder and the like. The device is installed on the inner side of two ship boards of a dock wall of the floating dock. The device can meet requirements for two kinds of docking and lying and ensure accurate lying position. The two kinds of docking and lying conditions are characterized in that the ship is guided into a dock for lying when the floating dock is submerged, or an air bag is utilized to load maritime work structural objects to enter the dock for lying when the floating dock is contacted with a wharf in abutting mode. In addition, the device has auxiliary fastening effect on products to be transported in the floating dock transportation process. The device is installed on the dock wall of the floating dock and is capable of accurately and quickly conducting safe lying location on the products entering the dock in controllable mode in the ship guiding load receiving process. The device has the advantages of being concise in mechanism, simple to operate, accurate in location, convenient to install and low in cost and also has the advantages of hydraulic program control and rigidity limit.