The utility model provides a three-phase alternating-current switching power supply device and system. The device comprises a transformer primary side circuit, a three-winding transformer, a first output rectifying circuit, a second output rectifying circuit, a switching circuit, an output filtering circuit and a control circuit. The transformer primary side circuit samples the three-phase alternating current input voltage and transmits a sampling result to the control circuit; the input voltage is input into the three-winding transformer; a three-winding transformer carries out voltage transformation processing, and transmits the voltage to an output filter circuit through a first output rectification circuit or a second output rectification circuit. The control circuit is used for receiving the sampling result and comparing the sampling result with a preset switching voltage Vset to control the working state of the switching circuit; the switching circuit is used for switching the connection states of the first and second output rectifying circuits and the output filter circuit; the output filter circuit outputs the voltage processed by the first or second output rectifier circuit. The wide-range input characteristic of the three-phase alternating-current switching power supply is improved.