Abstract: According to the system requirement, the laser and mid-wave infrared composite guidance optical system was designed. The infrared working wavelength of the system was 3m~5m, the laser wavelength was 1.064 m, the receiving diameter of the system was 250 mm, F number was 1.4, the value of MTF was greater than 0.4 at 33 lp/mm, the optical transmittance was greater than 60%, the infrared focal plane array was 640512 pixels, and each pixel was 15 m15 m.The secondary imaging with refractive and reflective structure was used to deal with the athermalization and compact problem.