A child-mother type double-wheel rotor steam powered machine is disclosed, including a child-wheel rotor and a mother-wheel rotor arranged within the case body and mounted on a same rotation shaft, wherein a hole-slot and a hole-slot facing a same direction are arranged on the peripheral of the child-wheel rotor and the peripheral of the mother-wheel rotor; one end of the rotation shaft is fitted with an inertial flywheel and a power output wheel, and the other end is fitted with a cam control output wheel; an exhaust pipe is provided on the bottom of the case body; a spray head is provided on the top of the case body, and inlets of the child-wheel air boring and the mother-wheel air boring of the spray head are connected to a high pressure steam inlet pipe respectively; a valve switch is arranged above the mother-wheel nozzle; the cam control output wheel is connected to a transmission device with a cam, and the cam is capable of controlling the action of the valve switch. The child-mother type double-wheel rotor steam powered machine of the present invention uses environment-friendly and renewable clean energy source, especially high pressure steam, to propel a machine for doing work, which can save energy, and is beneficial for popularization and utilization due to its simple configuration.