This paper describe a novel method to measure bipolar electrostatic field, by an electronic shutter which is based on the principle of charging and discharging of capacitance, modulating the DC signal to AC. By adjusting the direction of diode to allow an electric current to pass in one direction, it can hold the valley voltage of negative electrostatic field measurement or hold the peak voltage of positive electrostatic field measurement. Comparing to mechanical shutter, such as quartz tuning fork, electronic shutter is more durable, and less likely to face temperature drift. Besides, it has high sampling rate, capturing more information at fixed time. By using the method, we get more reliable, repeatable, and linear results. The SNR can up to 175, the error is under 4%, which is proved beyond the conventional measuring technique with the shutter of mechanical type.