Abstract: The present invention relates to a system and method of routing packets using an IP address in portable Internet, in which an individual IP address is given to a portable Internet terminal attempting to access the portable Internet via a certain radio access station, thereby routing packets without interruption of a packet data service using the IP address. According to the present invention, in a portable Internet system, a routing path for the packet data service is updated in real time using an IP address given to a respective portable Internet terminal while the terminal is moved, thereby continuously using the packet data service without an interruption in the service while the terminal freely moves to a different radio access station.