Function multiplexing microwave photon down-conversion method

The invention discloses a function multiplexing microwave photon down-conversion method, which comprises a laser, an electric coupler, a power divider, a dual polarization quadrature phase shift keying (DP-QPSK) and the like, and is characterized in that received microwave signals including a radio frequency signal RF, an interference signal SI and a mirror image signal IM are transmitted to the DP-QPSK through the DP-QPSK; and meanwhile, a reference signal SR applied to interference elimination and a local oscillator signal LO used for frequency conversion are modulated to the optical carrier. Radio frequency self-interference elimination is realized by adjusting a bias voltage working point of the X-DPMZM and optimizing an electric delayer and an electric attenuator of the loaded SR branch; in an LO loading branch, by adjusting a Y-DPMZM bias voltage working point, reconfigurable local oscillator frequency multiplication down-conversion is realized; orthogonal polarization sideband signals output by DP-QPSK