The invention discloses data transmission method when the route region is refreshed. The method comprises following steps: MS requires the new SGSN of new route region to attain the PDP context from the old SGSN of old route region when the route region is refreshed in SGSN; the new SGSN arranges the tunnel to each PDP context after receiving the PDP context from old SGSN and arranges the IP address of relative PDP context to each tunnel, then, sending the relation between distributed tunnels and IP addresses to the old SGSN; the old SGSN transmits the data of each PDP context to the new SGSN via relative tunnel. The inventive method solves the problem that old SGSN can only transmit the data to unique address in present technique, so the new SGSN should relates to distribution modules for distributing data. The invention can make the transmission of user's data more flexible when the route region of SGSN is refreshed, simplify the design of system and shorten the refresh time of route region. |