Embodiments of this application provide a screen sharing method and a related device. The method may be applied to a first system. The first system includes a first device, a second device, and a third device. The first device communicates with the second device through a first connection, and the first device communicates with the third device through a second connection. The first connection is different from the second connection. The method includes: The first device receives a first operation, where the first operation is used to trigger sharing of a first interface. The second device displays the first interface, and the third device displays the first interface. The first device displays a second interface, where the first interface is different from the second interface.