In order to improve the soybean quality and the seed purity, the surface physical properties of both soybean and cocklebur were analyzed, and the experiments of the removing pattern, adhesion mechanism and separating time were made on different materials in laboratory. Based on the experiments and analysis, 5QC-1.0 soybean and cocklebur separator has been designed and manufactured.The machine is reliable and cocklebur can be separated from soybean completely.