The invention relates to a phase-polarization multi-freedom-degree-modulation QKD (quantum key distribution) network system and method. The system comprise an Alice transmitting end, a WDM (wavelength division multiplexing) unit and a multi-user Bob end, wherein the Alice end is connected with the multi-user Bob end through the WDM unit, and the Alice end comprises a multi-wavelength laser generating device, an attenuator, a first polarization beam splitter, a first beam combiner, a phase modulator, a first polarization controller and a second polarization controller; the WDM unit comprises a wavelength selecting device; the multi-user Bob end comprises a plurality of unit Bob user ends for receiving different wavebands, and each unit Bob user end comprises a second polarization controller, a third polarization controller, a fourth polarization controller, a third polarization beam splitter, a fourth polarization beam splitter, a second beam combiner, a third beam combiner, a first photon detector, a second photon detector, a third photon detector and a fourth photon detector. The QKD network system has the advantages that one-to-many quantum key sharing, information transmission capacity is expanded effectively, and the system is applicable to a phase-polarization multi-freedom-degree-modulation QKD scheme and other QKD schemes.