The invention discloses an integrated structure of a double-path output S band relay power amplifier. A splitter divides signals of an input end into two paths, and the signals are respectively sent to a 13W microwave amplification link and a 2W microwave amplification link; the 13W microwave amplification link is connected with a first output end to perform the output of 13W power of an S band, and the 2W microwave amplification link is connected with a second output end to perform the output of 2W power of the S band; a DC/DC power supply conversion circuit is connected with a primary power supply through a power supply interface network and converts the voltage of the primary power supply into a second voltage matched with the 13W microwave amplification link and the 2W microwave amplification link; the 13W microwave amplification link and the 2W microwave amplification link are respectively connected with the DC/DC power supply conversion circuit to perform respective independent power supply; and a power supply switch control circuit is separately connected with two DC/DC power supply conversion circuits corresponding to the 13W microwave amplification link and the 2W microwave amplification link, and the power supply switch control circuit controls the DC/DC power supply conversion circuits so as to supply power to the 13W microwave amplification link and/or the 2W microwave amplification link.