Embodiments of the present application disclose a switching method and an access network device. The switching method comprises: on a terminal device switching from a first control plane core network device to a second control plane core network device, a first access network device sending a tunnel setup request message to a second access network device; the first access network device receiving information of a data tunnel established by the second access network device according to the tunnel setup request message; and the first access network device sending information of the data tunnel to the terminal device, wherein the information of the data tunnel is used for data transmission between the terminal device and a user plane core network device. The embodiments of the present application can improve reliability of data transmission.