Disclosed is a broadcast/communication unified passive optical network system. The network system comprises: an optical line termination that time-division multiplexes the received digital broadcast signals, receives communication signals through the internet, and wavelength-division multiplexes and transmits the broadcast signals and the communication signals; a plurality of optical network units connected to the optical line termination in one-to-multi connection, each optical network unit receiving the broadcast signals and the communication signals from the optical line termination, time-division demultiplexing the broadcast signals, and sending the broadcast signals selected from the above broadcast signals in accordance with a subscriber control signal and the communicating signals; and, a plurality of setup boxes connected to the each optical network unit in one-to-multi connection, each setup box receiving the broadcast signals and communication signals from each corresponding optical network unit and sending the subscriber control signal inputted by a subscriber to the corresponding optical network unit.