The utility model discloses a well head anti-theft pressure release blowout preventer, which is applied to an oil extraction port of an oil field. The lower end of an upper joint is connected with an annular outer anchor tile seat; four anchor tiles are suspended on the wall of the anchor tile seat; a nut is arranged on an annular step in the lower end of the anchor tile seat and is arranged in a central hole at the lower end of the upper joint; the upper end of a central pipe is in threaded connection with the nut; the inner wall of the upper end of the central pipe is provided with a polygonal axial hole; an annular valve seat is fixed through a threaded hole of the central pipe; the lower part of the valve seat is provided with a steel ball and a compression spring; the lower end of the central pipe is in threaded connection with a base cone; an outer central pipe is sleeved on the outer wall of the central pipe; the lower end of the outer central pipe is in threaded connection with an annular rubber drum sleeve, a rubber drum and an isolating ring; and the top of the upper rubber drum is provided with a cone sleeve. The well head anti-theft pressure release blowout preventer has the effects of realizing effective plugging of the well head, pressure release of a shaft, illegal mining prevention and protection over the shaft and guaranteeing smooth implementation of bailing operation.