Method for adaptive traversal through network address translator (NAT) in session initiation protocol (SIP) call

The invention discloses a method for adaptive traversal through a network address translator (NAT) in a session initiation protocol (SIP) call. The traversal through the NAT is finished by adaptively analyzing the equipment condition of the NAT and determining an optimal media transport path. By the method, the optimal media transport path can be selected according to a priority sequence by detecting network conditions; a priority strategy can be set according to the actual conditions of a user, the using cost of a transfer server can be lowered if a network type sequencing strategy is used, and optimal media transport quality can be achieved if a round-trip time (RTT) value sequencing strategy is used; and the extended attributes of a service discovery protocol (SDP) are used, so that the standard of the SDP cannot be destroyed.