In order to simulate the spectral distribution difference betw een the target and the interference in real scene, a zoom optical engine w ith tw o channels and the same caliber has been designed based on dual digital micro-mirror device ( DM D) , it includes projection optical system and tw o illumination optical systems. The optical engine directly illuminates tw o DM D target surfaces respectively w ith long-w ave infrared ( LWIR) and mid-w ave infrared ( M WIR) Kohler telecentric beam. It uses spatial stereoscopic layout to get avoid of interference betw een different optical paths. The design result show s that the illuminance uniformity of illumination optical system is better than 94%. The modulation transfer function ( M TF) values of zoom projection optical system are better than 0. 4 and better than 0. 7 at 101 p/mm respectively in bands of LWIR ( 8 ~ 12 μm) and M WIR ( 3. 7 ~ 4. 8 μm) . And the distortion is better than 0. 5%, w hich meet the requirements.