The present disclosure discloses a method, device, and system for controlling screen projection. The method comprises a first terminal acquiring a device list, wherein the device list includes identification information of a second terminal, and the second terminal is a terminal that accesses a same server as the first terminal; the first terminal receiving a selection instruction, wherein the selection instruction is used to select target identification information from the device list; the first terminal sending a screen projection control instruction to the server, wherein the screen projection control instruction includes target identification information, and the screen projection control instruction is forwarded to a target second terminal corresponding to the target identification information via the server, so as to control the target second terminal to project the screen to a first screen projection receiving end.