The invention discloses a phase noise calibrating device based on a photoelectric fusion technique, which comprises a microwave amplifier (2), a power divider (3), a phase shifter (4), a modulator (5), an attenuator (6) and a phase noise measurement system (10), and further comprises a photoelectric oscillator (1), a microwave noise source (9), a broadband amplifier (8) and a band-pass filter (7). The photoelectric oscillator is developed through the photoelectric fusion technique, so the phase noise calibrating device has a large phase noise standard dynamic range and a simple structure, and can calibrate the phase noise measurement result precision, so the defects of the existing calibrating method are overcome, and thus, the phase noise measurement result precision traceability of a microwave frequency band is obtained.