The method for establishing a connection by a HNB comprising steps of: the HNB transmitting an "attachment request" message to an operation and maintenance center (OMC); the OMC transmitting an "attachment response" message to the HNB; the HNB establishing a connection with an MME indicated by the "attachment response" message. With the method proposed in the present invention, a UE can switch between HNBs in the same CSG through interface X2. Meanwhile, such information as the radio resource management and so on can be exchanged between two HNBs.