A server and method for a short message service (SMS) that can improve the chances of success in short message service message transmission to a mobile communication terminal subscribed in both a public land mobile network (PLMN) and a private wireless network in an interworking system where the public land mobile network and the private wireless network interwork with each other. The short message service server transmits a message according to a request through an Internet protocol (IP) network to a private mobile switching center (pMSC) of a private wireless network system, and if there is a response indicating a failure of the transmission received from the private mobile switching center, designating the failed message as a predetermined public short message service message type, storing the message of the public short message service message type in a message queue, and requesting the short message service to a server of a public land mobile network system through the Internet protocol network.