Abstract: In order to meet the application of the ultraviolet(UV) warning systems in military domain,an optical system of a solar-blind ultraviolet warning system was designed with binary diffractive elements and aspherical elements.Its working wavelength is 240nm～280nm,full field of view is 40°.It is composed only of five lenses with "negative-positive" reverted-telephoto type.The lens has simple structure,small size,and high energy concentration.The results show that this design is a good solution to the UV-axis lens aberration correction,the spot is less than pixel size of UV-CCD,making point diagram with high energy concentration,and satisfying the design requirement of UV warning systems.