A method for transferring an IP transmission session is disclosed, including the following: a transmission session is created between the first node and second node based on a single IP protocol; the first node and second node obtain a transferable address pair by exchanging the session transfer management signaling; the transferable address pair is checked for bidirectional reachability; the transferable address pair is available if reachable in both directions, or is not available if unreachable in either direction; and the transmission session is transferred through the available transferable address pair. An apparatus for transferring an IP transmission session is also disclosed. Through the technical solution under the present disclosure, a session can be transferred in a network where IPv4 coexists with IPv6 without substantially affecting continuity of the end-to-end transmission session, thus fulfilling the requirements in the transition period during which IPv4 coexists with IPv6.