Embodiments of the present invention relate to the communications field, and provide a branching tower-mounted amplifier and an antenna feed system, so that a branching tower-mounted amplifier is added on an antenna unit side, thereby implementing a function of a four-port RRU, ensuring network coverage, and improving network performance. The branching tower-mounted amplifier includes a first filter module, a second filter module, a first amplification module, a second amplification module, a control module, a first branching module, and a second branching module.