Composite sealing back rubber mat

The utility model relates to the technical field of gaskets, in particular to a composite sealing back rubber gasket which comprises a metal gasket, an upper rubber gasket and a lower rubber gasket, the upper rubber gasket is arranged on the top end face of the metal gasket, and the lower rubber gasket is arranged on the bottom end face of the metal gasket. The top face of the upper rubber gasket is a conical face inclining downwards from outside to inside, the conical face is provided with at least two circles of protruding rings arranged at intervals in the radial direction, and the top point of each protruding ring is flush with the edge of the upper rubber gasket. A release film is arranged on the bottom surface of the lower rubber gasket, and a layer of adhesive coated on the bottom surface of the lower rubber gasket is arranged between the lower rubber gasket and the release film. The bottom surface of the lower rubber gasket is provided with the back glue layer formed by the adhesive, and after the ext