A method for processing a multiplexing packet with Real-time Transport Protocol, RTP, header compression, for use in a network comprising a transmitter, a first Media Gateway, MGW1, a Mobile Switching Center Server, MSC Server, and a second Media Gateway, MGW2, wherein the transmitter is a Base Station Controller, BSC, or a Radio Network Controller, RNC, the method comprising: obtaining, by the MGW1, the transport format for multiplexing with RTP header compression corresponding to the transmitter and the MGW2; receiving, by the MGW1, a multiplexing packet with RTP header compression transmitted by the transmitter; decompressing, by the MGW1, the received multiplexing packet with RTP header compression into at least one packet according to a transport format for multiplexing with RTP header compression corresponding to the transmitter; compressing, by the MGW1, the at least one packet according to the transport format for multiplexing with RTP header compression corresponding to the MGW2; and transmitting, by the MGW1, the compressed packet to the MGW2; wherein the step of obtaining, by the MGW1, the transport format for multiplexing with RTP header compression corresponding to the transmitter comprises: receiving, by the MGW1, an indication message transmitted by the MSC Server, wherein the indication message carries an interface type of an interface corresponding to the transmitter; and determining, by the MGW1, that the transport format for multiplexing with RTP header compression corresponding to the transmitter is a SIP-based transport format for multiplexing with RTP header compression if the interface type is A interface or Iu interface. obtaining, by the MGW1, the transport format for multiplexing with RTP header compression corresponding to the transmitter and the MGW2; receiving, by the MGW1, a multiplexing packet with RTP header compression transmitted by the transmitter; decompressing, by the MGW1, the received multiplexing packet with RTP header compression into at least one packet according to a transport format for multiplexing with RTP header compression corresponding to the transmitter; compressing, by the MGW1, the at least one packet according to the transport format for multiplexing with RTP header compression corresponding to the MGW2; and transmitting, by the MGW1, the compressed packet to the MGW2; wherein the step of obtaining, by the MGW1, the transport format for multiplexing with RTP header compression corresponding to the transmitter comprises: receiving, by the MGW1, an indication message transmitted by the MSC Server, wherein the indication message carries an interface type of an interface corresponding to the transmitter; and determining, by the MGW1, that the transport format for multiplexing with RTP header compression corresponding to the transmitter is a SIP-based transport format for multiplexing with RTP header compression if the interface type is A interface or Iu interface. receiving, by the MGW1, an indication message transmitted by the MSC Server, wherein the indication message carries an interface type of an interface corresponding to the transmitter; and determining, by the MGW1, that the transport format for multiplexing with RTP header compression corresponding to the transmitter is a SIP-based transport format for multiplexing with RTP header compression if the interface type is A interface or Iu interface.