The relevant development status of solar blind ultraviolet and infrared warning is reviewed. According to current application demands for the missile warning payload in near-space, a dual-band early warning system is presented, which covers the solar blind ultraviolet 250~280 nm and middle wavelength infrared (MWIR) 3 000~5 000 nm. The dual-band system is used to realize the detection and warning to military targets such as missile, which can effectively reduce the false alarm rate. A three-mirror off-axis system is taken as the main anti-optical system and the splitter is used to realize beam splitting on two spectral bands. According to the detector used by the optical systems on two bands and the corresponding application needs, the structure calculation and optical design of the optical system are completed. After the design is completed, the modulation transfer function (MTF) of two bands of the optical system at Nyquist frequency are solar blind ultraviolet MTF>0.8@39 lp/mm and MWIR MTF>0.8@17 lp/mm respectively. The maximum root mean square (RMS) spot diameter of two optical systems is smaller than the size of a detector and the single cell energy concentration is greater than 80%.