Disclosed herein are a combined communication and broadcasting dual switching system and method. The system includes broadcasting transmission means, an Optical Line Terminal (OLT), an optical detection unit, an active path determination unit, an optical switch unit, and a combining unit. The broadcasting transmission means converts a Radio Frequency (RF) broadcast signal into an optical signal. The OLT includes dual lines and selectively outputs an Internet data signal. The optical detection unit detects a line from which the Internet data signal is being output. The active path determination unit determines that the line is an active path. The optical switch unit receives the optical signal from the broadcasting transmission means, and switches to the active path. The combining unit receives the optical signal output after having been switched, receives the Internet data signal from the OLT, and multiplexes the received optical signal and the received Internet data signal.