The utility model discloses a composable plate type belt pressure sealing device which comprises a sealing plate. A to-be-sealed container is attached to the lower surface of the sealing plate to carry out belt pressure seal, a combined device is positioned on the lateral edge of the sealing plate, and plurality of belt pressure sealing devices can be in lap joint through the combined device to form a combined belt pressure sealing device. A plurality of permanent magnet switches capable of adjusting magnetic attraction force are arranged in the sealing plate, permanent magnet blocks are arranged in the permanent magnet switches, control rotating shafts are arranged on the permanent magnet blocks, the magnetic field direction of the permanent magnet blocks are perpendicular to the axial direction of the vertical rotating shafts, the magnetic attraction force of the permanent magnet switches can be adjusted by rotating the rotating shafts, and parts of the rotating shafts exposed of the upper surface of the sealing plate form a match section matched with a rotating tool. The plate type belt pressure sealing device is good n sealing effect, small in magnetic force before carrying out belt pressure sealing and easy to locate. The magnetic force lines of the permanent magnet switches are sealed so as to be strong in magnetic attraction force. In dismounting, the plate type belt pressure sealing device can be adjusted to be in a small magnetic attraction force state so as to be easy to dismount.