The invention discloses an asymmetrical multi-level power converting circuit. The asymmetrical multi-level power converting circuit comprises a first direct current power source, a second direct current power source, a switch capacitance unit, a first full bridge circuit and a second full bridge circuit. Through regulating a proportion value of the first direct current power source and the seconddirect current power source, and controlling the on-off of each full control switch, a constant direct voltage is converted to multi-level alternating current output, and while the output is the positive-negative double level and positive-negative septuple level of the first direct current power source, the capacitance of the switch capacitance unit is located in a discharging state; and while theoutput is not the positive-negative double level and positive-negative septuple level of the first direct current power source, the capacitance of the switch capacitance unit is located in a chargingstate. It is known that the asymmetrical multi-level power converting circuit can output the multi-level alternating current by just two input power sources, the number is small, and the devices areless. The circuit is simple in structure. Only if the output is the positive-negative double level and positive-negative septuple level, the capacitance is located in the discharging state, and otherstates are located in the charging state, so the capacitance has the smaller voltage ripple.