Embodiments of this application provide a communication method and apparatus. The method includes: A terminal device receives a first handover message from a first access network device, where the first handover message indicates the terminal device to switch, to a second cell, from a first cell in which the terminal device is currently located, and the second cell is a cell managed by a second access network device. The terminal device performs first data transmission with the second access network device based on the first handover message by using a secret key of the first cell. According to the method, it can be ensured that duration of communication interruption that occurs when the terminal device performs cell switch is short.