As a key component of mechanized maize harvesting, the performance of the ear picking device directly affects the operational level of a maize harvester. Because the short harvest period of maize and the multiple experimental factors that lead to the field and bench tests cannot meet the actual research and developmental needs of manufacturing a maize harvester, this paper uses virtual prototype technology to study the influence of design and the motion parameters of a longitudinal horizontal roller in terms of picking performance. Based on the establishment of the finite element model of the corn and the ear picking device, this paper establishes evaluation indicators respectively, analyzes and evaluates the influence of the picking roller and the ground inclination angle, the picking roller speed, and the forward speed of the harvester on the performance of ear picking. Finally, a virtual orthogonal test analysis was carried out for the two factors of the picking roller speed and the forward speed of the harvester, and the significant influence of the picking roller speed and the forward speed of the harvester on the performance of the picking was compared. The research results of this paper can provide reference for optimizing the design of ear picking mechanism.