Abstract: A projection system and a control method thereof are provided. The projection system includes a projector. The projector comprises a projection module and a processor. The processor is electrically coupled to the projection module. The projector confirms whether a first triggering event is detected and turns on a sleep aid mode in response to the first triggering event. The sleep aid mode corresponds to at least one control parameter. In the sleep aid mode, the projection module plays at least one multimedia file according to the at least one control parameter. The processor adjusts at least one parameter value of the at least one control parameter to adjust the at least one multimedia file correspondingly. The projector confirms whether a second triggering event is detected and the projection module stops playing the at least one multimedia file and turns off the sleep aid mode in response to the second triggering event.