Abstract: With the aim of solving the lack of theoretical design methods for the mechanical structure of the rotor system of the rubber roller huller, a new equivalent design method was proposed, which fully considered the hulling yield and the geometric size of paddy. Firstly, the relationship between the paddy hulling yield, the geometric size of paddy grains and the geometric size of rubber roller and its rotational speed were established by equivalent the paddy hulling yield to the contact area of paddy on the rubber roller. Secondly, the relationship between the rubber roller extrusion force and the physical properties of the paddy and the rubber roller was established by equivalent the extrusion deformation of the rubber roller to the extrusion force of the paddy grains between the rubber rollers. Finally, the relationship between the paddy hulling power and the paddy hulling yield, the geometric size of paddy and rubber roller was established by equivalent the extrusion force between the rubber rollers to the external load of the rotating shaft. Meanwhile, a method to evaluate the rationality of paddy hulling power by using the rotational power determined by the moment of inertia of rubber roller was established. The design calculation example showed that when the designed paddy hulling yield was 2.5 t/h, the long axis 2a was 9 mm and the short axis 2c was 2.5 mm of the paddy grains, the calculated parameters such as the motor power, the rubber roller speed and the rubber roller length were in good agreement with the MLGQ(T)25 of rubber roller huller. Therefore, this method is reliable and effective, and can provide theoretical guidance for the optimization design and performance analysis of rubber roller huller.