This application discloses a state configuration method and a device, including: determining, by a terminal device, that a transmission configuration indicator TCI state configured by a network device changes; obtaining, by the terminal device, a first TCI state configured by the network device before the TCI state changes; configuring, by the terminal device, a second TCI state to be the same as the first TCI state; and when the second TCI state is the same as the first TCI state, a reference signal pointed by using the second TCI state and a reference signal pointed by using the first TCI state are quasi co-located; and after the TCI state changes and before a third TCI state configured by the network device is activated, sending and receiving, by the terminal device, data by using the second TCI state.