Abstract: The paper presents a design of all-solid-state pulsed power generator based on Marx generator with MOSFET semiconductor switch devices. Charging resistance is replaced by fast recovery diode in the circuit, which reduces power loss in charging process. Drive circuit is integrated in and gets power supply from main circuit. Optical fiber is used to deliver the drive signal so as to protect it from the interference of discharging. A clockwise/counter-clockwise ring-shaped compact configuration is applied, which reduces the loop inductance, and makes the generator modularized and compact. The proposed generator is composed of 180 Marx unites in series, each of which is charged at a low voltage of 900 V, and generates a fast output pulse of voltage 150 kV, rise time less than 500 ns and duration adjustable between 1 and 5 s. Some experimental results of the pulsed power generator are listed, with a load of 50 k resistance and 5 pF capacitance in parallel. Through comparison and analysis, some factors affecting the rise time of output pulses are summarized, including loop inductance, drive voltage of MOSFET and distributed capacitance of main circuit. Approaches for pulse rise time improvement are also discussed.