A message processing method with respect to a terminal having multiple External Identifiers, EIDs, the method comprising: receiving, by a Machine Type Communication Inter Working Function, MTC-IWF entity, a triggering request from a Machine Type Communication, MTC server (S301, S401); requesting, by the MTC-IWF entity, a Home Subscriber Server, HSS, for information of the terminal according to the triggering request message (S302, S402); receiving and storing, by the MTC-IWF entity, the information of the terminal sent by the HSS (S303, S403), wherein the information of the terminal comprises an identifier of a SMS Service Center, SMS-SC, serving the terminal and an International Mobile Subscriber Identity, IMSI of the terminal; sending, by the MTC-IWF entity, a triggering message to the SMS-SC (S304, S404), wherein the triggering message comprises an EID and the IMSI of the terminal, or comprises the IMSI and a triggering-specific identifier of the terminal, the triggering-specific identifier is configured by the MTC-IWF entity after storing the information of the terminal and is added into the information of the terminal; wherein the triggering-specific identifier has a format as same as that of a Mobile Subscriber ISDN, MSISDN number of the terminal, the triggering-specific identifier is MSISDN-Trigger; transmitting, by the SMS-SC, a Short Messaging Service, SMS message carrying the triggering message to a terminal after receiving the triggering message (S305-S309, S405-409), wherein responsive to the triggering message comprising the EID of the terminal, the SMS message contains a Transmission Protocol Data Unit, TPDU, in which a destination address, TP-DA parameter is set as a Local Identifier, LID of the EID; or responsive to the triggering message comprising the triggering-specific identifier of the terminal, the SMS message contains a Transmission Protocol Data Unit, TPDU, in which a destination address, TP-DA parameter is set as the triggering-specific identifier configured for the terminal; receiving, by the SMS-SC, a triggering response from the terminal and sending the triggering response to the MTC-IWF entity (S309-311, 409-411); retrieving, by the MTC-IWF entity, the EID corresponding to the terminal according to the LID or triggering-specific identifier carried in the triggering response (S312, 412); and sending, by the MTC-IWF entity, to the MTC server a triggering request report according to the retrieved EID (S313, 413), the triggering request report comprising the EID. receiving, by a Machine Type Communication Inter Working Function, MTC-IWF entity, a triggering request from a Machine Type Communication, MTC server (S301, S401); requesting, by the MTC-IWF entity, a Home Subscriber Server, HSS, for information of the terminal according to the triggering request message (S302, S402); receiving and storing, by the MTC-IWF entity, the information of the terminal sent by the HSS (S303, S403), wherein the information of the terminal comprises an identifier of a SMS Service Center, SMS-SC, serving the terminal and an International Mobile Subscriber Identity, IMSI of the terminal; sending, by the MTC-IWF entity, a triggering message to the SMS-SC (S304, S404), wherein the triggering message comprises an EID and the IMSI of the terminal, or comprises the IMSI and a triggering-specific identifier of the terminal, the triggering-specific identifier is configured by the MTC-IWF entity after storing the information of the terminal and is added into the information of the terminal; wherein the triggering-specific identifier has a format as same as that of a Mobile Subscriber ISDN, MSISDN number of the terminal, the triggering-specific identifier is MSISDN-Trigger; transmitting, by the SMS-SC, a Short Messaging Service, SMS message carrying the triggering message to a terminal after receiving the triggering message (S305-S309, S405-409), wherein responsive to the triggering message comprising the EID of the terminal, the SMS message contains a Transmission Protocol Data Unit, TPDU, in which a destination address, TP-DA parameter is set as a Local Identifier, LID of the EID; or responsive to the triggering message comprising the triggering-specific identifier of the terminal, the SMS message contains a Transmission Protocol Data Unit, TPDU, in which a destination address, TP-DA parameter is set as the triggering-specific identifier configured for the terminal; receiving, by the SMS-SC, a triggering response from the terminal and sending the triggering response to the MTC-IWF entity (S309-311, 409-411); retrieving, by the MTC-IWF entity, the EID corresponding to the terminal according to the LID or triggering-specific identifier carried in the triggering response (S312, 412); and sending, by the MTC-IWF entity, to the MTC server a triggering request report according to the retrieved EID (S313, 413), the triggering request report comprising the EID.