A handover method, comprising: triggering, by a first access network device, a second access network device and a terminal device to configure a second protocol stack, the second protocol stack being configured to maintain at least one of: a sequence of data packets between the second access network device and the terminal device, or a security key of the data packets between the second access network device and the terminal device; and before the first access network device triggers the second access network device to maintain the sequence of the data packets of the terminal device by use of the second protocol stack through second triggering information, sequentially processing, by the first access network device, data packets to be processed of the terminal device by use of a first protocol stack; when triggering the second access network device and the terminal device to configure the second protocol stack, maintaining, by the first access network device, a connection between the first access network device and the terminal device, the first access network device not releasing the first protocol stack, functions of a PDCP layer of the first protocol stack, and the connection between the first access network device and the terminal device, and notifying, by the first access network device, the terminal device not to release the first protocol stack and the functions of the PDCP layer of the first protocol stack and to maintain the connection between the terminal device and the first access network device until triggering the second access network device to use the second protocol stack through the second triggering information, characterized in that the second triggering information, sent to the second access network device, is any one of Radio Resource Control, RRC, signaling, Medium Access Control, MAC, signaling, or Downlink Control Information, DCI. triggering, by a first access network device, a second access network device and a terminal device to configure a second protocol stack, the second protocol stack being configured to maintain at least one of: a sequence of data packets between the second access network device and the terminal device, or a security key of the data packets between the second access network device and the terminal device; and before the first access network device triggers the second access network device to maintain the sequence of the data packets of the terminal device by use of the second protocol stack through second triggering information, sequentially processing, by the first access network device, data packets to be processed of the terminal device by use of a first protocol stack; when triggering the second access network device and the terminal device to configure the second protocol stack, maintaining, by the first access network device, a connection between the first access network device and the terminal device, the first access network device not releasing the first protocol stack, functions of a PDCP layer of the first protocol stack, and the connection between the first access network device and the terminal device, and notifying, by the first access network device, the terminal device not to release the first protocol stack and the functions of the PDCP layer of the first protocol stack and to maintain the connection between the terminal device and the first access network device until triggering the second access network device to use the second protocol stack through the second triggering information, characterized in that the second triggering information, sent to the second access network device, is any one of Radio Resource Control, RRC, signaling, Medium Access Control, MAC, signaling, or Downlink Control Information, DCI.