A method for rejecting received SIP messages which are redundantly retransmitted used in a Session Initiation Protocol (SIP) application architecture. In one embodiment, the method comprises: forwarding all the messages transmitted from a SIP application server to a SIP terminal, and dropping all the received SIP messages redundantly retransmitted from the SIP terminal to the SIP application server according to the transmission direction of said SIP messages; and correspondingly replying to the dropped SIP messages according to the message type thereof. The present invention also provides a corresponding retransmission rejection device and a network device comprising the same, and further provides a method and device for rapidly rejecting redundantly retransmitted SIP messages in the case where the memory space is limited. The present invention can be applied to a network device such as a SIP stateless proxy at a front end of a SIP application server cluster.