Abstract: This paper studies the characteristics of the time and frequency domains of solar arrays during electrostatic discharge, to improve the understanding as well as the technical support of the charge-discharge mechanism of solar arrays. In the test, the main structure of the solar arrays is isolated from the ground of the vacuum chamber and an electron gun is used to simulate the electrified environmental extremes in the geostationary earth orbit. Specimens are electronically irradiated and charged by the electron gun. The current strength and shape are recorded, as well as the electrical field, by the monopoles, the CT-2 current detector(1 mV/mA) and the TerkDPO4104 digital storage oscilloscope. The electrostatic discharge is initiated by the electrostatic potential of the surface charged solar arrays. A transient current is activated during the discharge and its pulse width reaches 10^-6 s. A degraded ring-wave current can be observed and the detected pulse peak reaches several Amperes. The solar array electrostatic discharge field sustains from 10^-7 to 10^-6 s. The irradiation field strength is 10³ V/m and the spectrum ranges up to 10² MHz. A pulse cluster is the characteristics of the solar array time domain, showing a steep-front, with the frequency ranging from 0.1~50 MHz. Suggestions are made accordingly with regard to the property of onboard ESD test instruments.