The large-scale corn thresher automatically feeds materials, saving labor and time, as long as the preliminarily dried corn cobs are stacked on the site, and driven by the tractor drive shaft, the feeding is automatically completed, saving the trouble of manual feeding, and Greatly improved work efficiency. Double cleaning, high removal rate and low crushing rate, double cleaning includes secondary cleaning by mesh screen and air suction cleaning. The mesh screen device effectively separates the corn kernels from the broken corncob, and removes them through the suction device. Light and small particles are suitable for a variety of operating sites, and it is more convenient to use with the clutch device of a diesel engine with more than 18 horsepower. When not in operation, the newly added clutch device separates the thresher from the power equipment, which not only reduces the fuel consumption of the power equipment, but also facilitates downtime for maintenance. . High efficiency, high removal rate, low crushing rate Double drum design, higher efficiency.