The invention relates to a six-level circuit topology for a power conversion system, the circuit comprises a left circuit composed of first to fifth busbar capacitors connected in series in the same direction in turn, A first switching device A1, second switching device A2, third switching device A3, fourth switching device A4, fifth switching device A5, the sixth switching device A6 is sequentially connected in series on the right side, a first intermediate circuit composed of a ninth switching device A9, a second intermediate circuit composed of a seventh switching device A7 and a tenth switching device A10 in series, a third intermediate circuit composed of an eighth switching device A8 and an eleventh switching device A11 in series, a fourth intermediate circuit composed of a twelfth switching device A12, and three clamping capacitors. The invention can effectively reduce switching loss and voltage harmonics in the circuit, and can also control flexibly in controlling the switchingtransistor, and can be applied to power conversion devices such as inverters.