Abstract: A power supply processing device includes three electric control valve groups, a positive output terminal and a conversion control switch group. The conversion control switch group includes a selection switch group configured to selectively connect the current valve control components in each electric control valve group to the positive output terminal or the phase output terminal, and a connection switch group configured to connect or disconnect a current path between two electric control valve groups connected one another. In such a way, both AC experiments and DC experiments of high voltage and large capacity may be performed to the connectors without changing experimental site and experimental equipment, thereby effectively reducing the experimental cost.