Abstract: In order to overcome the disadvantages of using the conventional mechanical methods to explore marine Co-rich crust, such as crushing head wearing easily, low efficiency and high dilution ratio, we developed a new technology using experimental investigation, in which the pulse power techniques were used to explore the marine Co-rich crust. A power source was designed using solid-state Marx circuits together with semiconductor switch IGBT, which could generate negative high voltage pulses with rising edge 100 ns and maximum amplitude 40 kV. The breaking way adopted needle-needle electrodes which contact the same surface of rocks closely. To improve the potential of areas where the needles contact with the surface of rocks, stainless pins were used as the electrodes. Results indicate that plasma channels were generated and sandstones were broken when the amplitude of high voltage pulse was 32.5 kV and the distance between electrodes was 3 mm. Moreover, discharges happen either during the rising-time or after the rising-time of high voltage pulses. The changing curves of voltage and current show the plasma channels have variable impedance during discharge processes.