The invention discloses a foldable full-hydraulic well drill for a drill tower. The well drill includes a well drill body which mainly comprises a transport vehicle and a drilling component on the plate of the transport vehicle, wherein the transport vehicle includes a tower body; the bottom of the tower body is movably hinged at the tail end of the plate of the transport vehicle through a tower body hinging seat, and the upper end of the middle part of the tower body is fixedly connected with the head end of a hydraulic strut through bolts and flanges. The well drill is provided with a slide rail which is provided with a T-shaped chute on the outer surface, and a slide block of a T-shaped structure, wherein the slide block is embedded into the T-shaped chute in a sliding mode, so that the slide block can slide in the moving direction of the T-shaped chute, and the slide block and the slide rail adopt a limiting structure. In this way, a sliding guide frame accordingly avoids the condition of the sloshing of a power head, so that in the process of the power head lifting, the relative distance between the power head and the tower body does not change greatly, so as to ensure the stability of the equipment in use.