During real-time monitoring of high voltage corona discharge, the solar radiation intensity is much higher than the radiation generated by corona discharges, which will interfere with the detection process. However, due to the absorption of the earth's ozone layer, the radiation intensity of the sun's radiation to the ground becomes very weak in the solar-blind ultraviolet band of 240~280 nm. Observing high-voltage wires in this band can reduce the interference of the environment, thereby improving the imaging contrast and reducing the false detection rate. In order to expand the detection range and improve the detection accuracy of the solar-blind UV imaging system, the optical system needs to have a higher resolution while ensuring a larger field of view. In this paper, a solar-blind ultraviolet optical system with a large field of view, large relative aperture and high resolution is designed. We have formulated the design index according to user needs, and selected an anti-telephoto lens as the initial structure according to the design index requirements. During optimization, we first replaced the lens material with fused silica and calcium fluoride materials commonly used in the ultraviolet band. According to the principle of chromatic aberration correction, the positive lens is replaced by calcium fluoride with a large Abbe number, and the negative lens is replaced by fused silica with a small Abbe number. The refractive index of these two materials is low and the Abbe number difference is small in the solar-blind ultraviolet band, which is not suitable for chromatic aberration correction, and the typical achromatic structure doublet lenses can not transmit ultraviolet radiation, so we added two sets of double separation structures to correct chromatic aberration. Due to the high requirements for the surface roughness of the lens in the ultraviolet band, the limitation of materials and apertures, and the consideration of technological difficulty, no aspherical lens was introduced in this design. The final design uses 12 standard spherical lenses, with a total optical length of 90 mm, a full field of view of 56°, and a relative aperture of 1/2. In the full field of view, the distortion is less than 2.2%, the relative illumination is greater than 70%, the Modulation Transfer Function (MTF) of the system is greater than 0.65 at the spatial frequency of 110 lp/mm, and the optical system has good imaging quality. After that, we analyzed the thermal defocusing caused by the thermal deformation of the lens and lens barrel materials and the thermally induced refractive index change of the optical material in the temperature range of -20~60 ℃. The results show that the MTF of the system decreases significantly when the ambient temperature changes. The thermal defocus amount of the system has an approximate linear relationship with the temperature change, so we can use the passive mechanical compensation method to correct the thermal difference of the system. We use ABS plastic with high coefficient of linear expansion as the compensation lens barrel to compensate for thermal defocusing. The MTF of the compensated system is greater than 0.4 in the working temperature range, realizing athermal design. Finally, through reasonable tolerance allocation, the MTF of the tangential and sagittal directions of the system after processing and adjustment decreases relatively uniformly under the influence of tolerances. Under the probability of 80%, the MTF at the Nyquist sampling frequency of the system is greater than 0.35, and the system still maintains a high imaging quality, which meets the actual requirements of corona detection.