The invention relates to a passive static triangle common path interference imaging spectral full-polarization detecting device, which comprises a fronting optical telescopic system. The rear part of the fronting optical telescopic system is provided with a static all-optical modulating module; the rear part of the static all-optical modulating module is provided with a Sagnac static interference imaging spectrometer; the rear part of the Sagnac static interference imaging spectrometer is provided with an imaging mirror group; the rear part of the imaging mirror group is provided with a detector which is connected with a signal acquiring and processing system; after light which is emitted by a target source is collimated and then subjected to phase modulation, the modulated transmission light is changed into two beams of parallel polarized light; the two beams of light are converged on the detector after passing through the imaging mirror to form the image and generate interference; and then a signal received by the detector is sent to the signal acquiring and processing system to be processed. The device has the characteristics of simple and compact structure, no moving parts, large light quantity and capability of acquiring target two-dimensional space images, one-dimensional spectral information and complete polarization information once.