The invention provides an infrared dual-band optical engine based on dual digital micromirror devices (DMDs). The infrared dual-band optical engine comprises a protection optical system, a first DMD,a second DMD, a first lighting optical system and a second lighting optical system, wherein the first DMD is used for modulating incident infrared long-wave light to infrared long-wave image light, the second DMD is used for modulating incident infrared medium-wave light to infrared medium-wave image light, and the first lighting optical system and the second lighting optical system are respectively arranged at two sides of an optical axis of the protection optical system and are used for respectively irradiating target surfaces of the first DMD and the second DMD with the infrared long-wave light and the infrared medium-wave light. The dual lighting optical systems are used for respectively and directly irradiating the target surfaces of the first DMD target and the second DMD target, interference among different optical paths is prevented by employing space three-dimensional layout, and the energy utilization rate is effectively improved; dual-band chromatic aberration correction ofthe infrared long wave and the infrared medium wave is completed by introducing two non-spherical surfaces to the protection optical system, and the front non-focusing design is achieved; and by the optical engine, the infrared dual-band simulation scene can be projected, and the energy distribution difference of different infrared bands in an image surface in the scene also can be simulated.