The present document discloses a method and apparatus for updating a local gateway (LGW) address. The method may include a destination donor NodeB receiving local gateway address assignment information and, according to the local gateway address assignment information, if the destination donor NodeB determines that an IP address is required to be assigned to a local gateway co-located in a mobile relay node, then assigning an IP address to the local gateway, and sending the IP address of the local gateway to a service gateway. An apparatus, located in the destination donor NodeB, may include a receiving module, an assigning module, and a sending module. Another apparatus, located in the mobile relay node, may include a judgment module and a storage module. Another apparatus, located in the service gateway servicing a UE, may include a receiving module and an updating module.