Abstract: The design of the dual-channel collimating projection optic system was introduced. The parameters distribution of the optic system and the optimization by using the multi-configuration function of ZEMAX optical software were discussed. The overall tolerances were analyzed through Monte Carlo analysis. The optic system adopted the combination of the telescope system and the imaging system. The beam splitter was located in the parallel light-path between the telescope system and the imaging system to combine the first target source channel with the second target source channel. The operating range of the optical system is 8 μm~12 μm, the field of view is 12°, the focal length is 228.3 mm, the entrance pupil distance is 800 mm, the maximum angular resolution of target channel 1 and target channel 2 are 0.18 mrad and 0.17 mrad, respectively, which meet the design requirements of the projection system.