The invention discloses an automatic hydraulic unhooking device. The automatic hydraulic unhooking device comprises an oil cylinder, an automatic
hooking device and a hydraulic
system for controlling the pressure of a rod cavity of the oil cylinder, wherein the automatic
hooking device is fixed at the end part of a
piston rod of the oil cylinder; the automatic hydraulic unhooking device is also provided with mechanical locks, and the mechanical locks are mounted on an outer cylinder wall of the oil cylinder in pairs; an unlocking
rope is arranged on the mechanical locks; an unhooking
rope is mounted between the automatic
hooking device and the mechanical locks; one end of the unhooking
rope is connected with the automatic hooking device, and the other end of the unhooking rope is connected with the mechanical locks. According to the automatic hydraulic unhooking device disclosed by the invention, a hammer is lifted by the mechanical locks, and the hydraulic bearing of a high-speed oil cylinder is replaced by the rigid bearing of a mechanical-lock structure, so that the problem that when the
heavy load of the high-speed oil cylinder is lifted, a
piston rod slides off is solved; the
working pressure in the high-speed oil cylinder is low, and the sealing, manufacturing and maintenance cost is low; the
piston rod of the high-speed oil cylinder is unlocked by the mechanical locks through the traction of the unlocking rope, so that the automatic hydraulic unhooking device is simple and convenient to operate, high in reliability, and suitable for
impact machinery to perform unhooking operation.