The present disclosure discloses a distributed antenna system. The DAS includes a signal source, a first signal generator, a first passive mixer, and a first antenna. The first signal generator is configured to: generate a first local-frequency signal, and send it to the first passive mixer by using a passive DAS line. The first passive mixer is configured to receive the first local-frequency signal, and a downlink radio frequency signal having a second radio frequency band. The first passive mixer is further configured to: perform frequency mixing processing on the received downlink radio frequency signal having the second radio frequency band by using the first local-frequency signal, to form a first downlink radio frequency signal having a first radio frequency band, and then send it to the first antenna. The first antenna is configured to transmit the received first downlink radio frequency signal having the first radio frequency band.