Embodiments of the present disclosure provide a multi-frequency band antenna feeder sharing method and a base station radio frequency unit. The method includes: receiving a signal of a frequency band 1 and a signal of a frequency band 2 through an antenna feeder, transmitting the signals to a band-pass filter and filtering the signals so as to obtain the signal of the frequency band 2, and transmitting the signal of the frequency band 2 to a third radio frequency port through a combiner port; and/or, sending the signal of the frequency band 2 to the combiner port through the third radio frequency port, transmitting the signal of the frequency band 2 that has passed through the band-pass filter to the port of the first radio frequency channel, and sending out the signal of the frequency band 2, together with the signal of the frequency band 1.