Abstract: A 10-staged low impedance Marx generator is designed, whose volume is about 0.12 m3and output power and pulse width are more than 30 GW and 200 ns respectively. The generator is charged synchronously with positive and negative voltages. Its triggered-switch is three-electrode field distortion switch and other switches are over-voltage self-breakdown switches. After optimization design, the heights of the self-breakdown switches and triggered switch are 33, and 42 mm, and the inductances are 13.1 and 15.2 nH, respectively. The positive and negative electrodes of the capacitor are pressed within the switchs electrode. The insulator within the electrodes of the capacitor is 100 layers of polypropylene, whose total thickness is about 2 mm, and it can withstand the voltage over 100 kV. Additionally, Maxwell 3D simulation shows that, the inductance of the electrode connecting plate is 4.16 nH in this connection manner. Pspice circuit simulation and experiment show that, when the capacitor is charged at 100 kV, the output voltage is more than 600 kV and the peak current is about 50 kA on the 12 load.