Provided are a method and signaling gateway for establishing an optimized media path applied in an IMS network. The method includes: during the process of forwarding a session description protocol (SDP) request and response, when receiving a SDP response of a first session, a first ALG judging that there is an optimized media path between itself and a second ALG, then when sending the SDP response of the first session, including indication information in the send SDP response; the first ALG sending a SDP request with the target being the second ALG; and after having received the SDP response of the first session including the indication information or after having received the SDP request with the target being the second ALG and the SDP response of the first session including the indication information, the second ALG sending the SDP response of the first session.