A radio-frequency power converter and a radio-frequency transmission system for magnetic resonance imaging are provided in embodiments of the present invention. The radio-frequency power converter comprises a printed circuit board, the printed circuit board comprises a first circuit layer, a ground layer, and one or a plurality of intermediate layers located between the first circuit layer and the ground layer. A plurality of planar spiral inductors connected in parallel are formed on the first circuit layer. One ends of the plurality of inductors are connected to each other and respectively connected to one end of a first capacitor, the other ends of the plurality of inductors are respectively connected to one ends of a plurality of second capacitors, and the other ends of the plurality of second capacitors are all grounded.