A method and system for accessing a local network by a mobile terminal via a home base station system are provided. The method comprises: a home base station subsystem, in which the mobile terminal is located, sending an ID of a local gateway module in the home base station subsystem to a core network management network element, and the core network management network element determining that the mobile terminal needs to access the local network, and setting up a GPRS tunneling control bearer with the home base station subsystem according to the ID, so that the mobile terminal can access the local network via the home base station subsystem. The method and the system makes the core network acquire the address of the local GGSN/PDN-GW corresponding to the home base station without manual configuration, thus reducing the complexity of the network configuration.