The invention discloses a vacuum discharge detection device of an electronic gun. The device comprises a light guiding system (5), a CCD imaging device, a photoelectric sensor module, a signal processing module and a display module. The light guiding system (5) is respectively connected with the CCD imaging device and the photoelectric sensor module through extreme ultraviolet optical fibers, the photoelectric sensor module is connected with the signal processing module, the CCD imaging device and the signal processing module are respectively connected with the display module, and the light guiding system (5) is arranged on the wall of a vacuum chamber where the electronic gun is located or a high-voltage ceramic bottle wall at the front end of the vacuum chamber to be used as a probe. Extreme ultraviolet light generated in the process of vacuum discharge of the electronic gun is utilized by the device for analyzing the vacuum discharge intensity of the electronic gun, and the CCD imaging device conducts exposure imaging on the vacuum discharge of the electronic gun, and conducts positioning on the discharge position.