A data exchange method, wherein the method comprises: receiving, by a secondary base station, a first message sent by a primary base station, or receiving relationship information of a secondary base station and a primary base station configured by an operation, administration and maintenance system, OAM, wherein the first message is used for notifying the secondary base station to set up an S1 interface; sending, by the secondary base station, an S1 interface setup request to the primary base station; receiving an S1 interface setup response sent by the primary base station; and performing, by the secondary base station, exchange with the primary base station by using the S1 interface; wherein if the primary base station allows the S1 interface setup, the S1 interface setup response carries an inter-base station coordinated service identifier; wherein after the receiving an S1 interface setup response sent by the primary base station, the method further comprises: sending, by the secondary base station, a downlink transport network layer address, TNL address, and a General Packet Radio Service Tunneling Protocol tunnel endpoint identifier, GTP TEID, of the secondary base station to the primary base station, so that the primary base station sends the downlink TNL address and the GTP TEID of the secondary base station to a serving gateway, SGW, via a mobility management entity, MME, and the secondary base station receives an uplink TNL address and a GTP TEID of the SGW that are sent by the primary base station; and the method further comprises: sending, by the secondary base station to the SGW, received uplink data sent by UE, and sending, by the secondary base station to the UE, received downlink data sent by the SGW. receiving, by a secondary base station, a first message sent by a primary base station, or receiving relationship information of a secondary base station and a primary base station configured by an operation, administration and maintenance system, OAM, wherein the first message is used for notifying the secondary base station to set up an S1 interface; sending, by the secondary base station, an S1 interface setup request to the primary base station; receiving an S1 interface setup response sent by the primary base station; and performing, by the secondary base station, exchange with the primary base station by using the S1 interface; wherein if the primary base station allows the S1 interface setup, the S1 interface setup response carries an inter-base station coordinated service identifier; wherein after the receiving an S1 interface setup response sent by the primary base station, the method further comprises: sending, by the secondary base station, a downlink transport network layer address, TNL address, and a General Packet Radio Service Tunneling Protocol tunnel endpoint identifier, GTP TEID, of the secondary base station to the primary base station, so that the primary base station sends the downlink TNL address and the GTP TEID of the secondary base station to a serving gateway, SGW, via a mobility management entity, MME, and the secondary base station receives an uplink TNL address and a GTP TEID of the SGW that are sent by the primary base station; and the method further comprises: sending, by the secondary base station to the SGW, received uplink data sent by UE, and sending, by the secondary base station to the UE, received downlink data sent by the SGW.