The point discharge is a kind of discharge phenomenon which is produced by the sharp point of the object. It belongs to a kind of corona discharge. It has been widely used in lightning rod and electrostatic dust removal technology. At present, the research on point discharge is mainly focused on the discharge intensity, and the research on its spectrum is not much. In this paper, it is found that the point discharge has strong radiation in the ultraviolet band. The ionization characteristics of the tip discharge were simulated by Comsol software, and the discharge spectrum was analyzed by means of mathematical physics model. In addition, the ionization characteristics of the point discharge are simulated by Comsol software. The radiation spectrum and radiation intensity of the discharge are analyzed by the mathematical physical model. The radiation intensity is first increased and then decreased with time, and the UV band can be estimated according to the distribution intensity of N2+ of the radiation intensity. The ultraviolet spectrum of the point discharge was analyzed by three ultraviolet spectra channels. The results show that the emission spectrum of the point discharge is distributed in the 240～340 nm band, 340 nm is the strongest. At the same time, the intensity of ultraviolet radiation of the point discharge decreases with the increase of the tip distance, and has a linear relationship with the imaging integration time. Besides, the linear slope decreases with the tip distance increasing in the same channel. The quantitative relationship between the radiation energy and the tip distance, the tip voltage and the integration time is obtained, and the mathematical model of the point discharge is validated. It is shown that, for the first time, this study provides a solid support for the depth study of UV discharge characteristics of the tip.