An image projection system includes a scaler IC, a micro-projector, a video connector, and a controller. The video connector is coupled to the scaler IC and the micro-projector. The controller controls the video connector and the scaler IC to form a first signal path mode and a second signal path mode. The video connector transmits a first image signal from the scaler IC for external displaying in the first signal path mode. The video connector receives a second image signal from a peripheral device and passes the second image signal to the micro-projector for projection in the second signal path mode.