Embodiments of the present disclosure provide a multi-connectivity communication method and a device. An access network device of an LTE network sets up a second connection for UE and splits data of the UE through the second connection. The second connection is a connection set up between the UE and the access network device of the LTE network through an access network device of a next generation network. Therefore, dual connectivity between the UE and the LTE network and the next generation network is implemented, a data transmission rate of the UE is increased, and a throughput of the entire network can be increased.