Abstract: A positionable hidden hydraulic hinge configured for installation of a door is provided. The positionable hidden hydraulic hinge includes a non-movable device body configured to be connectable with a door frame, a rotatable device body configured to be connectable with a door leaf, and a hinge configured to connect the non-movable device body and the rotatable device body. The rotatable device body includes a bearing guiding base having a guiding groove and a hydraulic chamber body. The positionable hidden hydraulic hinge also includes a linkage assembly configured to penetrate throughout the hinge. Two ends of the linkage assembly are configured to pivotably connect with the non-movable device body and an internal mechanism of the rotatable device body, respectively. A first end of the bearing guiding base is fixedly connected with the hinge, and a second end of the bearing guiding base is connected with the hydraulic chamber body.