Abstract: Self-discharge biconical antenna is an important part of the compact electromagnetic pulse radiation system, which determines the gap discharge excitation voltage insulation design and far-field output voltage is of great significance for the research of the entire system. This paper presents an indirect method for measurement of antenna discharge excitation voltage by measuring the charging current of pulse source to the antenna. Static antenna is equivalent to a small capacitor. When starting to work, the source of the antenna is charged when the charging voltage reaches a certain level, the discharge gap breakdown, the antenna radiate electromagnetic energy by fast high voltage pulse excitation. The parasitic capacitance of the antenna is measured first, then the charging current of the antenna is measured by a broadband Rogowski coil, and voltage of the antenna can be obtained by integrating the charging current. Compared with a direct measurement, the method does not need to transform the antenna, has no introduction of parasitic parameters, does not affect the test subjects working conditions, and is easy to implement in engineering.