The invention discloses a polarization resolution differential reflection spectrum measuring system, comprising a liquid nitrogen Dewar, a manual three-dimensional translation stage, an achromatic lens, an exciter used for vibrating a lens periodically, a wide band quarter wave plate, a dual-output Gran-Taylor prism, a wide band linear polarizer and a wide band half wave plate, a monochromator, an ultra continuous white light source, a detector, two phase-locked amplifiers and a chopper. By utilizing the system disclosed by the invention, the polarization resolution differential reflection spectrum of a sample at 77-300K can be measured by adopting a low temperature Dewar, thus the energy band structure and characteristics of substances related to spin can be researched and analyzed.