The invention discloses a load matching device and a load matching method for a high-voltage pulse power supply. M switches are coupled together in a serial manner to form a complete switching group module. In the m switching groups, pulse voltages generated by the switching groups are not completely identical due to different turn-on and turn-off sequences and delays; the required high-voltage pulse can be generated at an output end after the pulse voltages are overlapped. The switching group module is controlled by the control module, and can directly receive control signals transmitted by the control module; under the effect of the control signals, the working state of each switching group in the switching group module can be controlled. Therefore, under the cooperation of the control module and the switching group module, the working state of the switching group is adjusted, the high-voltage pulse waveform of the output end can be adjusted, and thus the matching condition between the high-voltage pulse and load is improved, and matching between the high-voltage pulse and the load is achieved.