A practical electropulsing treatment device has been developed based on capacitor energy storage and discharge technology. The device was controlled by a pair of charge and discharge switches which close in turn to produce high density electropulsing. The electropulsing treatment experiment was carried out by capacitor discharging while an exponential damping oscillatory waveform was produced. A group of 45 steel quenched specimens were connected into the discharge circuit with copper electrodes through a vacuum contactor switch. At last, a typical waveform of electropulsing was detected by a DS5062MA digital storage oscilloscope. This waveform demonstrates that the first peak of electropulsing has reached 23 kA, and the discharging process has concluded within 0.6 ms. Results indicate that the energy density of electropulsing treatment is very concentrated because of the waveform of high peak value and short duration. The device is now being used for the stress relief processing of metals.