A video conference system including a first transmitter device and a receiver device is provided. The first transmitter device transmits a first video data. The receiver device includes a receiver control unit configured to assign a first identification code to the first transmitter device. The receiver control unit combines the first video data and a first identification image corresponding to the first identification code as a first combined video data and the receiver control unit outputs the first combined video data to the display device. Through the present invention, the conference participants can quickly identify which presenter is providing the video signal source corresponding to a particular frame on the split screen, and can raise questions to the right person.