Ultraviolet (UV) warning technology has been widely applied in missile approach warning. According to the user requirement, a solar blind UV warning optical system is designed for the wavelength range from 240~280 nm. In order to improve the luminous flux, expand the search scope and simplify system structure, an aspherical surface and binary optical elements are used. The initial optical data are based on the existing design that has a relative aperture of 14, the field of view of 30°, and consists of 6 pieces of lenses. As a result, the optical system is reduced to five pieces of lenses, the field of view is extended to 40°, and the relative aperture is increased to 13. PIXIS 2048BUV UV CCD whose pixel size is 13.5 μm×13.5 μm is applied as the detector. Image quality evaluation results show that this solar blind UV warning optical system is of high energy concentration, and the spot size is smaller than the pixel size of CCD, which satisfy the application requirements. The system has the advantages of large field of view and large relative aperture, and its technical characteristics are superior to the existing solar blind UV warning optical systems.