A method and a system for interworking with a Broadband Wireless Access (BWA) network in a Wireless Local Area Network (WLAN) terminal. According to the method, a relay station for connecting the Wireless Local Area Network (WLAN) terminal with the Broadband Wireless Access (BWA) network sets a connection with the Broadband Wireless Access (BWA) network through an initialization process. A user authentication with the Wireless Local Area Network (WLAN) terminal is performed by the relay station in compliance with a Wireless Local Area Network (WLAN) protocol. A user authentication with a Broadband Wireless Access (BWA) network Access Control Router (ACR) is performed in compliance with a Broadband Wireless Access (BWA) network protocol by the relay station in place of the Wireless Local Area Network (WLAN) terminal.