The structure introduction of a corn thresher is based on the principle that peeling and threshing can be completed twice. After peeling, part of the rotor can be replaced, and then the threshing rotor can be replaced to thresh without changing the motor. It is labor-saving, energy-saving, convenient, safe and reliable, with low power consumption and high operating efficiency. It is not only an ideal tool for farmers to relieve themselves from heavy physical labor, but also a good helper for agricultural machinery operators to obtain economic income. The machine is suitable for connecting diesel engines with less than 8 horsepower or household lighting electric motors.