The invention relates to a medium-voltage power distribution network frame structure based on a multi-port power electronic device. The medium-voltage power distribution network frame structure comprises four substations A, B, C and D, four switching stations a, b, c and d, and a four-terminal flexible direct-current loop closing device. Medium-voltage buses of the four transformer substations areconnected with the four switching stations through the four-terminal flexible direct-current loop closing device to form a double-petal wiring network structure. The medium-voltage bus of the transformer substation A, the medium-voltage bus of the transformer substation C and the four-terminal flexible direct-current loop closing device form one petal structure, and the medium-voltage bus of thetransformer substation B, the medium-voltage bus of the transformer substation D and the four-end flexible direct-current loop closing device form the other petal structure. According to the invention, the requirements for high flexibility and high reliability of a power supply area can be met.