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By means of analyzing corn stalk physical properties and rubbing mechanism, a conical corn stalk rubbing device was designed with 3D CAD software. It was mainly composed of hopper, cone, spline shaft and helical gears, and compared with other stalk rubbing devices, such as rubbing hammer, its structure was simplified. The forming principle of rasp bars was introduce, and the plane curve equation of rasp bars was derived, and then the space moving model of corn stalks, as well as status of the force being acted on corn stalk, was given when they were rubbed. Based on the design of algorithm routine for the corn stalks movement, virtual prototype tests were completed with Matlab software. The structure parameters and motion parameters of the virtual prototype were optimized. Finally, the prototype was trial-produced and tests were done, so its performance was tested, and the validity of the prototype was approved. 