Abstract: In order to improve the output waveform of the inductive energy storage pulse power source, this paper presents a quasi-square wave output pulse power source based on electric explosive opening switch(EEOS). This kind of pulse source uses a pulse capacitor as the initial energy storage, which discharges to the EEOS through the pulse forming network (PFN). The EEOS switches off when the discharge current nearly reaches the peak, thus the energy is switched to the load. Since the current in the PFN’s inductors can not be mutated, the load voltage can amount to several times the charging voltage of the storage capacitor. Due to the non-mutated voltages in the PFN’s capacitors, the load voltage can be quasi-square. Parameters of the EEOS and the age capacitor being charged to 32kV, the voltage on the 10Ω load is obtained as 83kV in amplitude, 279ns in FWHM, and about 172ns in full width at 90% magnitude, indicating that this kind of pulse power source is feasible.