A screen locking method and apparatus include establishing, by a first electronic device, a coupling to a second electronic device, sending, by the first electronic device, to-be-displayed data to the second electronic device to enable the second electronic device to display a first interface, and in this case, the first electronic device displays a second interface different from the first interface, obtaining, by the first electronic device, a first screen locking operation from a user, where the first screen locking operation instructs to lock a screen of the second electronic device, and sending, by the first electronic device, a screen locking instruction to the second electronic device in response to the first screen locking operation whereby the second electronic device enters a screen-locked state.