This application relates to wireless communication technologies, and more particularly, to a method, a apparatus and a system for transmitting a gateway address, which are used to solve the problem in the prior art that a DeNB is incapable of assisting an MME in selecting an SGW/PGW for a mobile relay node (RN). The method for transmitting a gateway address in an embodiment of this application comprises: a base station determining, when determining an access device to be a mobile RN, a gateway IP address of a mobility anchor serving as a gateway of the mobile RN; and sending the determined gateway IP address to a mobility management entity (MME) corresponding to the mobile RN. In the embodiment of this application, the DeNB is capable of assisting the MME in selecting a suitable mobility anchor for the mobile RN as the SGW/PGW, thereby guaranteeing normal work of the mobile RN.