Combustion produces blackbody radiation and free radical radiation. In order to obtain the ultraviolet radiation information produced by flame combustion, an UV optical system based on the needs of flame spectral information detection was designed. The design increases the working bandwidth of the ultraviolet optical system and improves the conventional field of view of the telephoto optical system. The system combines the characteristics of wide spectrum, large relative aperture, relatively large field of view and high resolution, so as to obtain more accurate flame ultraviolet spectral information in a large range. Thus the basic flame information such as flame fuel composition can be obtained and improve the applicability of the UV system. The operating wavelength of the system ranges from 240nm to 390nm, and the operating bandwidth is wide. The F-number of the system is 2.5, the relative aperture is large, and the field Angle of view is 15°. The whole system is composed of ten lenses, the total length is less than 170mm, and the compact structure meets all the basic requirements of combustion detection. The image quality evaluation results show that the root mean square radius of the dispersion spots in each field of view of the system is less than 9μm, the maximum lateral color aberration of the system is less than one pixel in the full wavelength range, the value of the modulation transfer function (MTF) is better than 0.5 at the cut off frequency of 50 (lp·mm-1), and the system distortion is less than 0.5%.The design results show that the ultraviolet optical system has the advantages of excellent imaging performance, wide working bandwidth, small chromatic aberration, high resolution, and small distortion, etc. At the same time all the lenses of the system are the spherical lenses, which is convenient for processing and detection, and meets the design requirements.