Duplexer, and manufacturing method thereof and multiplexer

The embodiment of the invention discloses a duplexer, and a manufacturing method thereof and a multiplexer, which can improve the integration level of the duplexer and reduce the size of the duplexer by integrating a transmitting filter and a receiving filter on the same substrate. In addition, the transmitting filter and the receiving filter can be manufactured on the same substrate at the same time and can share a film layer structure, so that the integration level of the duplexer is further improved, the size of the duplexer is further reduced, and the manufacturing cost of the duplexer is reduced. The transmitting filter and the receiving filter share one sealing ring structure, so that the occupied area of the sealing ring can be reduced; and the transmitting filter and the receiving filter are surrounded by the peripheral sealing frame body of the sealing ring, so that the structures of the transmitting filter and the receiving filter can be more compact, and the size of the duplexer can be further redu