In order to solve the field unification problem of aperture division of multi-angle polarimetric radiometer, and ensure the polarization measurement accuracy. A division of aperture optical path base on reflective telescope is proposed, then select two mirror beam expander program, calculate the initial structure parameters and optimize the system. The polarization effect of the new telescope system with silver mirror and the original telescope system with lens coated with λ/4 MgF2 are simulated and analyzed. The simulation results show that the new telescope system with silver film mirror has 0.258% of the maximum polarization effect at a shortest wavelength of 410 nm, lower than 0.1% at the other bands. It is better than the original system, or quite. The new telescope system can ensure the unity of the field of view of all bands and meet the condition of low polarization effect, and can replace the original transmission telescope system, and a polarization detection method based on the new telescope system is proposed. Finally, the advantages of the new detection method are summarized, and the flaws and countermeasures are pointed out, the application is also analyzed.