The invention relates to a permanent packer capable of being released and belongs to the field of underground operation tools for oil and gas wells. The permanent packer comprises a central pipe, a setting sleeve, a lock ring, a lining, a connecting sleeve, a rubber cylinder and a slip. A lower connector is installed at one end of the central pipe in a threaded mode. An upper conical body and a lower conical body are symmetrically arranged on the portion, on one side of the lower connector, of the central pipe. The slip is installed between the upper conical body and the lower conical body through a slip protection sleeve and a leaf spring. The other end of the central pipe is sleeved with the setting sleeve. The portion, on one side of the setting sleeve, of the central pipe is provided with the lining. The lining is in threaded connection with the setting sleeve. The slip of the packer is pressed by the leaf spring when entering a well and only stretches out when being pressed by the conical bodies under the action of hydraulic pressure, and the advanced setting risk of a conventional packer is effectively avoided. Firm anchorage can be guaranteed through the slip of the packer, the downward tooth shape can bear loads from the upper portion of the packer, and the upward tooth shape can bear loads from the lower portion of the packer. The slip is specially designed to be located below the rubber cylinder and used for blocking scraps, and the situation that the slip is jammed by the scraps during operation is avoided.