A network system and method of testing the terminal status so as to acquire the link status of the wired/wireless terminals associated to the VoIP-based network includes at least one user terminal which transmits a status message in response to a SIP-based Options message and a soft switch which transmits the Option message, determines whether or not the status message has been received, and recognizes whether the user terminal is in a Busy state or an Idle state based on a result of the determination. Since the terminal status can be accurately determined, it is possible to process calls, manage the terminal, and fairly charge the utilization costs to improve the stability and QoS of the network system.